Question

if you add the digits in a two-digit number and multiply the sum by 7, you get the original number. If you reverse the digits in the two-digit number, the new number is 18 more than the sum of its two digits. What is the original number?

Answer 1

Let m the tens digit and n the ones
the Original number is 10m+n
7(m+n) =10m+n
7m+7n=10m+n
6n=3m

Reversing the number 10n+m
10n+m=18+n+m
9n=18
n=2

6n=3m
6(2)=3m
3m=12
m=4
the number is 10m+n=10(4)+2=42