Question

Using digits 1,2,3,4 and 5 form a 2-digit and
3-digit number say ab and cde such that
ab x cde is maximum. What are the numbers?​

Answer 1

Answer:

Since AB and CD are two-digit integers, their sum can give us only one three digit integer of a kind of AAA: 111.

So, A=1 and we have 1B+CD=111

Now, C can not be less than 9, because no two-digit integer with first digit 1 (1B<20) can be added to two-digit integer less than 90, so that to have the sum 111 (if CD<90, so if C<9, CD+1B<111).

Hence C=9.