× logo

The Free 30-Day CAT RC Course

"It is designed to help you excel in the upcoming CAT 2024 exam"

-By Lavleen Kaur Kapoor. Over 2,00,000+ Subscribers

read more

No thanks >

Question

Given N is a positive integer less than 31, how many values can n take if (n + 1) is a factor of n!

CAT 2021

A
18
CORRECT ANSWER WRONG ANSWER
B
16
CORRECT ANSWER WRONG ANSWER
C
12
CORRECT ANSWER WRONG ANSWER
D
20
CORRECT ANSWER WRONG ANSWER
Solution

Correct option is

(A)

Explanatory Answer

According to ques , the number is a multiple of

if n! is a multiple of , it has to be a multiple of

the smallest factorial should be 24! , so , when n= 24, 25 or 26 , n! will be multiple of (not )

similarly ,we have to find n! such that it is a multiple of

but not . when n = 24 , 25 , 26 , 27 , n! will be multiple of but not

hence the smallest n from 24 , 25 , 0r 26 , will be 24 .

hence C is the correct option , "24 , 3"