JEE (Main)-2026 : Phase-1 (24-01-2026)-Evening

# Q1 of 58

The maximum value of n for which 40n divides 60! is equal to

Options
A.

11

B.

12

C.

13

D.

14

Show Answer
Correct Answer
D

14

Solution

To find the maximum value of
n
for which
40n
divides
60!
, we first express the number 40 in terms of its prime factors:

40=23×5

Therefore, we can write:
40n=(23×5)n=23n×5n

For
40n
to divide
60!
, the prime factor 2 must appear at least
3n
times in the prime factorization of
60!
, and the prime factor 5 must appear at least
n
times.

We can find the exponent of any prime
p
in
N!
using Legendre's formula:
Ep(N!)=Np+Np2+Np3+
where
x
represents the greatest integer less than or equal to
x
.

First, let us calculate the exponent of the prime 5 in
60!
:
E5(60!)=605+6025
E5(60!)=12+2=14
Since
5n
must divide
60!
, we have the inequality:
n14

Next, let us calculate the exponent of the prime 2 in
60!
:
E2(60!)=602+604+608+6016+6032
E2(60!)=30+15+7+3+1=56
Since
23n
must divide
60!
, we must have:
3n56
n563=18

To satisfy both constraints simultaneously, the value of
n
must satisfy:
nmin(14,18)=14

Therefore, the maximum value of
n
for which
40n
divides
60!
is equal to 14.

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