Quote:
How many zeros will be there in the value of 25!?
A. 25
B. 8
C. 6
D. 5
E. 2
The correct choice is (C) and the correct answer is 6.
Explanatory Answer
25! is factorial 25 whose value = 25*24*23*22*…..*1
When a number that has 5 as its factor is multiplied by another number that has 2 as its factor, the result will have ‘0’ in its units digit.
In 25!, the numbers that have 5 as their factor are 5, 10, 15, 20, and 25. 25 is the square of 5 and hence has two 5’s in it.
Therefore, 25! contains in it 6 fives.
There are more than 6 even numbers in 25!. Hence, the limiting factor is the number of 5s.
And hence, the number 25! will have 6 zeroes in it.
Here is one question from this document and I found its answer wrong there.
25! = 1.551121 × 10^(25) means 25 zeros in it.
Then how can it say that the number 25! will have 6 zeroes in it?