The number of 5 digit numbers which are divisible by 4, with digits from the set {1, 2, 3, 4, 5} and the repetition of digits is allowed, is ____.
Answer: 625
Solution
A number is divisible by 4 if its last two digits form a number divisible by 4.
From the set {1,2,3,4,5}, the two-digit numbers divisible by 4 are: 12, 24, 32, 44, 52 (5 possibilities).
The first three digits can be any of the 5 digits: ways.
Total: .
From the set {1,2,3,4,5}, the two-digit numbers divisible by 4 are: 12, 24, 32, 44, 52 (5 possibilities).
The first three digits can be any of the 5 digits: ways.
Total: .
JEE Advanced · 2018 · 20 May 2018 · Paper 1 · Numerical answer