Question

The total number of 5-digit numbers, formed by using the digits 1, 2, 3, 5, 6, 7 without repetition, which are multiple of 6, is 

(A) 36 

(B) 48 

(C) 60 

(D) 72

Answer 1

Correct option is (D) 72

To make a no. divisible by 3 we can use the digits 1,2,5,6,7 or 1,2,3,5,7. 

Using 1,2,5,6,7, number of even numbers is 

= 4 x 3 x 2 x 1 x 2 = 48 

Using 1,2,3,5,7, number of even numbers is 

= 4 x 3 x 2 x 1 x 1 = 24 

Required answer is 72.