Latest Infosys Aptitude Question SOLUTION: How many zeros are contained in 100!?

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(#M40021863) INFOSYS Numerical Ability question Keep an EYE

How many zeros are contained in 100!?

Asked In Infosys mageshrani (10 years ago)

Solved Dr.Dipin Singh Read Solution (14)

Is this Puzzle helpful?   (21)   (3) Submit Your Solution Data Interpretation

Read Solution (14) :

HARMEET KAUR  (10 years ago)

@ Narendra And Richa,
Number of zeros will depend on number of times multiple of 5,25,125 appear in the factorial of specified number.
in case of 100!,
multiples of 5 are 100/5=20
multiples of 25 are 100/25=4
so total zeros= 20+4=24

Is this solution Helpfull? Yes (25) | No   

Dr.Dipin Singh  (10 years ago)

zeros at end of 100!= 100/5 +100/25= 20+4=24

Is this solution Helpfull? Yes (20) | No (3)  

piyushgupta  (10 years ago)

24 is ans
100/5 + 100/25=24

Is this solution Helpfull? Yes (6) | No (5)  

Narendra  (10 years ago)

can any one explain clearly???

Is this solution Helpfull? Yes (6) | No (5)  

Laxmi Srinivas  (10 years ago)

24
100/5 = 20
20/5 =4
Answer:24

Is this solution Helpfull? Yes (5) | No (2)  

Saifulwara Mallick  (10 years ago)

Basic Explaination
5*2=10
5*5*2*2=100
and so on
Therefore, to solve the above problem you need to find the number of 5s and 2s contained in a number.
No of 5s in 100! = 100/5 + 100/(5^2)
= 20 + 4
= 24
No of 2s in 100! = 100/2 + 100/(2^2)+100/(2^3)+100/(2^4)+100/(2^5)+100/(2^6)
= 50 + 25 + 12 + 6 + 3 + 1
= 97
However no of 5s are only 24
so ans = 24
Shortcut Method : Always find highest number that is 5 = 24 ans

Is this solution Helpfull? Yes (4) | No   

varshika  (10 years ago)

24 zeroes
100/5=20
20/5=4
total 20+4=24

Is this solution Helpfull? Yes (3) | No (2)  

FRANKLIN VIJAY  (10 years ago)

11 zeros for 10, 20, 30, 40, 50, 60, 70,80, 90 and 100
plus there will be 10 zeros for 5, 15............95
for 75 , 25 and 50 there will be 3 additional 0's
so sum it up 11+10+3 = 24

Is this solution Helpfull? Yes (1) | No (14)  

bindu  (10 years ago)

there will be 24 zero's as upto 25! we have 6 zero's so same like that 6*4=24

Is this solution Helpfull? Yes (1) | No (6)  

Richa  (10 years ago)

can some one pls suggest as why 100 is being divided by 5 and 25? i mean pls explain d logic behind it.

Is this solution Helpfull? Yes (1) | No (1)  

nalin  (8 years ago)

100/5=20
and
100/25=4
so ,the total ans is 20+4=24
we r searching for 5 because 5*(any even number gives 0 at the unit place )
and another thing is the 25 contain two 5's .
That's why i have divided by 5 and 25 both for less then 100 .

Is this solution Helpfull? Yes (1) | No   

geetha  (10 years ago)

100!=10,20,30,40,50,60,70,90,100(totally 10 no of zero's)

Is this solution Helpfull? Yes | No (29)  

shuvodeep roy  (10 years ago)

the ans will be 11.

Is this solution Helpfull? Yes | No (2)  

Ankita Ghosh  (9 years ago)

24 zeros in 100!

Is this solution Helpfull? Yes | No   

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