Question

A seven-digit number comprises of only 2's and 3's. how many of these are multiples of 12?

Answer 1

see to make it divisible by 4 last two digits must be divisible by 4 so thats only one no. which is 32
and 3 twos and 4 threes,6 twos and one 3, makes it divisible by 3 .for ex 2 such no.s are
3323232,2222232
11 i think is the write answer
ask if any doubt
_ _ _ _ _ 3 2 now five places are left and you have 3 threes, so these 3 threes can be filled in 5C3=10 such numbers and 2222232 is the only no so that makes total 11