Two different digits from 1 to 9 are chosen randomly to form a 2-digit number. By reversing the order of

the digits, a second 2-digit number is formed. What is the probability that the sum of these two numbers will

be a multiple of the sum of the digits?

thedudethatneedshelp May 24, 2021

#1

#2**+1 **

I like this question, it is much easier than it looks

Let the first digit be x and the second by y

You might find it a little easier to think of two different scenarios. Though really this is not necessary.

1. x+y <10

2. x+y >10

However:

If you want to look in advance then just draw up a 9 by 9 grid, fill in the outcomes and see what happens.

**Please let 'thedude...' work it out for himself from here.**

Melody
May 24, 2021