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City X conducted a one-day study of accumulation patterns in a city-ow

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City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   31 Jan 2024, 00:13
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City X conducted a one-day study of accumulation patterns in a city-owned parking garage that contains a total of 1,200 parking spaces. The graph summarizes the cumulative arrivals (number of automobiles that had arrived at the garage), cumulative departures (number of automobiles that had departed the garage), and accumulation (number of automobiles occupying the garage) at one-hour intervals from 5:00 a.m. to 7:00 p.m. on the day of the study.

Each of the following options describes a condition that occurred at least once between 5:00 a.m. and 7:00 p.m. on the day of the parking study.
For each option, select Before 1:00 p.m. if the first such occurrence was before 1:00 p.m. Otherwise, select 1:00 p.m. or later.
Before 1:00 p.m. 1:00 p.m. or later
Cumulative arrivals were greater than accumulation.
Cumulative arrivals were greater than 2 times cumulative departures.
Cumulative departures were greater than accumulation.
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Cumulative arrivals were greater than accumulation.: Before 1:00 p.m. Cumulative arrivals were greater than 2 times cumulative departures.: Before 1:00 p.m. Cumulative departures were greater than accumulation.: 1:00 p.m. or later
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Re: City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   04 Mar 2024, 06:24
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­This is one of those questions that appears to be difficult but once you understand the dataset and primarily what the question is asking, the three statements can be solved very easily by simply looking at the graphs.



Again the key thing here is – understanding what the question is asking. Watch the video at 02:49 to see how you should understand what the question is asking so that your statement analysis is simplified.

Now one thing that I will caution you on – since it is a 3 series line chart and each statement compares two of these series, be sure to look at the correct lines.
­­­
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City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   31 Jan 2024, 03:53
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BottomJee wrote:
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City X conducted a one-day study of accumulation patterns in a city-owned parking garage that contains a total of 1,200 parking spaces. The graph summarizes the cumulative arrivals (number of automobiles that had arrived at the garage), cumulative departures (number of automobiles that had departed the garage), and accumulation (number of automobiles occupying the garage) at one-hour intervals from 5:00 a.m. to 7:00 p.m. on the day of the study.

Each of the following options describes a condition that occurred at least once between 5:00 a.m. and 7:00 p.m. on the day of the parking study.
For each option, select Before 1:00 p.m. if the first such occurrence was before 1:00 p.m. Otherwise, select 1:00 p.m. or later.


1. Cumulative arrivals were greater than accumulation.
Accumulation will never be greater than cumulative arrivals. The moment there is first departure, the cumulative arrivals will become more.
Clearly it happens much before 1 pm.

2. Cumulative arrivals were greater than 2 times cumulative departures.
Again the departures are very slow in the beginning. Accumulation is slightly less than Cumulative arrivals in first 2-3 hrs. Surely some departures have happened in tens, while cumulative arrivals are in thousands.
Again it happens much before 1 pm.

3. Cumulative departures were greater than accumulation.
The graph shows both equal at 2 pm and cumulative departures become more after 1 pm.

The solutions are straightforward and few questions could be added to make it a bit more challenging.

Q. At what time were cumulative arrivals exactly two times the cumulative departures.
8am, 9 am, 1 pm, 2 pm, 3 pm, cannot be determined.
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City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   Updated on: 02 Feb 2024, 09:07
chetan2u wrote:
BottomJee wrote:
Show Spoiler
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Graph pic.png

City X conducted a one-day study of accumulation patterns in a city-owned parking garage that contains a total of 1,200 parking spaces. The graph summarizes the cumulative arrivals (number of automobiles that had arrived at the garage), cumulative departures (number of automobiles that had departed the garage), and accumulation (number of automobiles occupying the garage) at one-hour intervals from 5:00 a.m. to 7:00 p.m. on the day of the study.

Each of the following options describes a condition that occurred at least once between 5:00 a.m. and 7:00 p.m. on the day of the parking study.
For each option, select Before 1:00 p.m. if the first such occurrence was before 1:00 p.m. Otherwise, select 1:00 p.m. or later.


1. Cumulative arrivals were greater than accumulation.
Accumulation will never be greater than cumulative arrivals. The moment there is first departure, the cumulative arrivals will become more.
Clearly it happens much before 1 pm.

2. Cumulative arrivals were greater than 2 times cumulative departures.
Again the departures are very slow in the beginning. Accumulation is slightly less than Cumulative arrivals in first 2-3 hrs. Surely some departures have happened in tens, while cumulative arrivals are in thousands.

3. Cumulative departures were greater than accumulation.
The graph shows both equal at 2 pm and cumulative departures become more after 1 pm.

The solutions are straightforward and few questions could be added to make it a bit more challenging.

Q. At what time were cumulative arrivals exactly two times the cumulative departures.
8am, 9 am, 1 pm, 2 pm, 3 pm, cannot be determined.


For 1. Cumulative arrivals were greater than accumulation.
If in the 2nd and 3rd questions, we can see the two lines in mention directly, why can't we only check the Cumulative arrivals line and the Accumulation line without considering Departure? If so,I think it's after 1pm cause in this period, gap between the Cumulative arrivals and the Accumulation are larger than before 1pm.
Again it happens much before 1 pm.

Originally posted by cathyjiang04 on 02 Feb 2024, 09:05.
Last edited by cathyjiang04 on 02 Feb 2024, 09:07, edited 1 time in total.
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Re: City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   02 Feb 2024, 09:06
chetan2u wrote:
BottomJee wrote:
Show Spoiler
Attachment:
Graph pic.png

City X conducted a one-day study of accumulation patterns in a city-owned parking garage that contains a total of 1,200 parking spaces. The graph summarizes the cumulative arrivals (number of automobiles that had arrived at the garage), cumulative departures (number of automobiles that had departed the garage), and accumulation (number of automobiles occupying the garage) at one-hour intervals from 5:00 a.m. to 7:00 p.m. on the day of the study.

Each of the following options describes a condition that occurred at least once between 5:00 a.m. and 7:00 p.m. on the day of the parking study.
For each option, select Before 1:00 p.m. if the first such occurrence was before 1:00 p.m. Otherwise, select 1:00 p.m. or later.


1. Cumulative arrivals were greater than accumulation.
Accumulation will never be greater than cumulative arrivals. The moment there is first departure, the cumulative arrivals will become more.
Clearly it happens much before 1 pm.

2. Cumulative arrivals were greater than 2 times cumulative departures.
Again the departures are very slow in the beginning. Accumulation is slightly less than Cumulative arrivals in first 2-3 hrs. Surely some departures have happened in tens, while cumulative arrivals are in thousands.
Again it happens much before 1 pm.

3. Cumulative departures were greater than accumulation.
The graph shows both equal at 2 pm and cumulative departures become more after 1 pm.

The solutions are straightforward and few questions could be added to make it a bit more challenging.

Q. At what time were cumulative arrivals exactly two times the cumulative departures.
8am, 9 am, 1 pm, 2 pm, 3 pm, cannot be determined.


For 1. Cumulative arrivals were greater than accumulation.
If in the 2nd and 3rd questions, we can see the two lines in mention directly, why can't we only check the Cumulative arrivals line and the Accumulation line without considering Departure? If so,I think it's after 1pm cause in this period, gap between the Cumulative arrivals and the Accumulation are larger than before 1pm.
Again it happens much before 1 pm.
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Re: City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   02 Feb 2024, 11:25
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cathyjiang04 wrote:
chetan2u wrote:
BottomJee wrote:
Show Spoiler
Attachment:
Graph pic.png

City X conducted a one-day study of accumulation patterns in a city-owned parking garage that contains a total of 1,200 parking spaces. The graph summarizes the cumulative arrivals (number of automobiles that had arrived at the garage), cumulative departures (number of automobiles that had departed the garage), and accumulation (number of automobiles occupying the garage) at one-hour intervals from 5:00 a.m. to 7:00 p.m. on the day of the study.

Each of the following options describes a condition that occurred at least once between 5:00 a.m. and 7:00 p.m. on the day of the parking study.
For each option, select Before 1:00 p.m. if the first such occurrence was before 1:00 p.m. Otherwise, select 1:00 p.m. or later.


1. Cumulative arrivals were greater than accumulation.
Accumulation will never be greater than cumulative arrivals. The moment there is first departure, the cumulative arrivals will become more.
Clearly it happens much before 1 pm.

2. Cumulative arrivals were greater than 2 times cumulative departures.
Again the departures are very slow in the beginning. Accumulation is slightly less than Cumulative arrivals in first 2-3 hrs. Surely some departures have happened in tens, while cumulative arrivals are in thousands.
Again it happens much before 1 pm.

3. Cumulative departures were greater than accumulation.
The graph shows both equal at 2 pm and cumulative departures become more after 1 pm.

The solutions are straightforward and few questions could be added to make it a bit more challenging.

Q. At what time were cumulative arrivals exactly two times the cumulative departures.
8am, 9 am, 1 pm, 2 pm, 3 pm, cannot be determined.


For 1. Cumulative arrivals were greater than accumulation.
If in the 2nd and 3rd questions, we can see the two lines in mention directly, why can't we only check the Cumulative arrivals line and the Accumulation line without considering Departure? If so,I think it's after 1pm cause in this period, gap between the Cumulative arrivals and the Accumulation are larger than before 1pm.
Again it happens much before 1 pm.



If the gap between accumulation and cumulative arrivals is increasing, then cumulative departures are increasing. Cumulative arrivals will be many more times of departure when accumulation is increasing. But the moment accumulation decreases, it means departures are increasing as compared to arrivals.
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City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   06 Feb 2024, 13:20
In my opinion, question 1 is not about whether the gap between cumulative arrivals and accumulation is getting bigger or not. Accumulation will never be greater than cumulative arrivals. The instructions for the question are: "For each option, select 'Before 1:00 p.m.' if the first such occurrence was before 1:00 p.m. Otherwise, select '1:00 p.m. or later'." It is not about if it just occurred before 1:00pm. Indeed, the first occurrence of the cumulative arrivals being greater than accumulation is before 1:00 pm. That's the reason this option is marked as "Before 1:00 p.m." Does "cumulative arrivals > accumulation" continue after 1:00 pm? Yes, but this doesn't invalidate the fact that the first occurrence of "cumulative arrivals > accumulation" was before 1:00 pm, which is the criteria the question says we use.
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City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   18 Apr 2024, 10:22
KarishmaB MartyMurray: I am lost in the question 1. Are we supposed to consider Arrival - departure = Accumulation? 
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Re: City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   18 Apr 2024, 23:28
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BottomJee wrote:
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Attachment:
Graph pic.png

City X conducted a one-day study of accumulation patterns in a city-owned parking garage that contains a total of 1,200 parking spaces. The graph summarizes the cumulative arrivals (number of automobiles that had arrived at the garage), cumulative departures (number of automobiles that had departed the garage), and accumulation (number of automobiles occupying the garage) at one-hour intervals from 5:00 a.m. to 7:00 p.m. on the day of the study.

Each of the following options describes a condition that occurred at least once between 5:00 a.m. and 7:00 p.m. on the day of the parking study.
For each option, select Before 1:00 p.m. if the first such occurrence was before 1:00 p.m. Otherwise, select 1:00 p.m. or later.

­
At every hour, accumulation would be "cumulative arrivals till that hour - cumulative departures till that time."
For example, At 10:00 AM cumulative arrivals are 1500 and cumulative departures are 300. Note that accumulation is 1200 at that time. 
Makes sense, right?
If someone tells you at 10:00 AM - till morning, 1500 cars have come in total and 300 cars have left. Can you say that 1200 cars are still inside the parking space? Sure. the good thing here is that they have already given you the amount of accumulation every hour so you don't need to calculate it. 


Cumulative arrivals were greater than accumulation.

Cumulative arrivals will always be either greater than or equal to accumulation (if no one leaves). By 6:00 AM, departures may be 0 so arrivals may be equal to accumulation but by 7:00 AM there were some departures too and arrivals became greater than accumulation.
Hence select "Before 1:00 PM"
@Engineer1 - The graph indicates when the departures started. 

Cumulative arrivals were greater than 2 times cumulative departures.

Look at 8:00 AM. Cumulative arrivals were many times greater than cumulative departures.
Hence select "Before 1:00 PM"

Cumulative departures were greater than accumulation.

Cumulative departures line is above the accumulation line for the first time at 3:00 PM. Hence Cumulative departures were greater than accumulation for the first time at 3:00 PM.
Hence select "After 1:00 PM"
 
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City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   19 Apr 2024, 07:32
KarishmaB wrote:
BottomJee wrote:
Show Spoiler
Attachment:
Graph pic.png

City X conducted a one-day study of accumulation patterns in a city-owned parking garage that contains a total of 1,200 parking spaces. The graph summarizes the cumulative arrivals (number of automobiles that had arrived at the garage), cumulative departures (number of automobiles that had departed the garage), and accumulation (number of automobiles occupying the garage) at one-hour intervals from 5:00 a.m. to 7:00 p.m. on the day of the study.

Each of the following options describes a condition that occurred at least once between 5:00 a.m. and 7:00 p.m. on the day of the parking study.
For each option, select Before 1:00 p.m. if the first such occurrence was before 1:00 p.m. Otherwise, select 1:00 p.m. or later.

­
At every hour, accumulation would be "cumulative arrivals till that hour - cumulative departures till that time."
For example, At 10:00 AM cumulative arrivals are 1500 and cumulative departures are 300. Note that accumulation is 1200 at that time. 
Makes sense, right?
If someone tells you at 10:00 AM - till morning, 1500 cars have come in total and 300 cars have left. Can you say that 1200 cars are still inside the parking space? Sure. the good thing here is that they have already given you the amount of accumulation every hour so you don't need to calculate it. 


Cumulative arrivals were greater than accumulation.

Cumulative arrivals will always be either greater than or equal to accumulation (if no one leaves). By 6:00 AM, departures may be 0 so arrivals may be equal to accumulation but by 7:00 AM there were some departures too and arrivals became greater than accumulation.
Hence select "Before 1:00 PM"
@Engineer1 - The graph indicates when the departures started. 

Cumulative arrivals were greater than 2 times cumulative departures.

Look at 8:00 AM. Cumulative arrivals were many times greater than cumulative departures.
Hence select "Before 1:00 PM"

Cumulative departures were greater than accumulation.

Cumulative departures line is above the accumulation line for the first time at 3:00 PM. Hence Cumulative departures were greater than accumulation for the first time at 3:00 PM.
Hence select "After 1:00 PM"



 

­Thank you, KarishmaB. Yes, I see that the cumulative arrival will always be greater than accumulation. Even the graph indicates that before or after 1:00 PM. Why is the answer only before 1PM? Arrival is always > accumulation, unless the data shows Departure has exceeded Arrival at some point. My reasoning is below.

I took the following data points and in every case it is A > AC.
At 7 AM, Arrival (A) = 250; Departure (D) ~ 50, thus, Accumulation (AC) = ~200
At 11 AM, A = ~1800, D = ~600, this, AC = ~1200
At 1 PM, A = ~2200, D = ~1100, this, AC = ~1100
At 4PM, A =~2450, D = 1600, thus AC = ~750
At 7PM, A =~2800, D = 2600, thus AC = ~200

So far I gathered that many of these DI questions are "intuitive" rather than involving complex calculations and data analysis. I am missing that intuition part. Any suggestion? Thanks.

 ­
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Re: City X conducted a one-day study of accumulation patterns in a city-ow [#permalink] New post   28 Apr 2024, 21:57
mmdfl wrote:
In my opinion, question 1 is not about whether the gap between cumulative arrivals and accumulation is getting bigger or not. Accumulation will never be greater than cumulative arrivals. The instructions for the question are: "For each option, select 'Before 1:00 p.m.' if the first such occurrence was before 1:00 p.m. Otherwise, select '1:00 p.m. or later'." It is not about if it just occurred before 1:00pm. Indeed, the first occurrence of the cumulative arrivals being greater than accumulation is before 1:00 pm. That's the reason this option is marked as "Before 1:00 p.m." Does "cumulative arrivals > accumulation" continue after 1:00 pm? Yes, but this doesn't invalidate the fact that the first occurrence of "cumulative arrivals > accumulation" was before 1:00 pm, which is the criteria the question says we use.

­Precisely
I made the same error. Was easy to miss the question stem in this one since the options appeared simple enough  :facepalm:
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Re: City X conducted a one-day study of accumulation patterns in a city-ow [#permalink]
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