Question

What is the largest possible five-digit number divisible by 12 that you can make from the digits 1,2, 3, 5 and one more digit?

Answer 1

75312  is the largest possible five-digit number divisible by 12 formed using digits 1,2,3,5 and one more

A number divisible by 12 should be divisible by 4 and 3.

"A number is Divisible by 4 if number formed by last 2 digits is divisible by 4"

12 , 32 , 52 are divisible by 4

As Number has to be largest so smallest number 12 should be used so that large digits are available for higher places.

"A number is Divisible by 3 if sum of digits is divisible by 3"

let say one more digit is X

Sum of Digits = 1 + 2 + 3 + 5 + X

= 11 + X  

12 , 15 , 18  are possible sum divisible by 3  

Hence X can be 1 , 4 , 7

X = 7  is largest possible digit here

Hence

75312   is  largest possible five-digit number divisible by 12