write two digit number nm as m + 10 n
m + 10n = 8 (n+m)
m + 10n + n + 10 m = 99
then solve the two equations
2 n = 7 m
11n+11m = 99 or n+m=9
n = (7/2)m
(7/2)m + m = 9
7 m + 2 m =18
9 m = 18
m = 2
n = 7
number = 72
This is a question with two equations, x, y each representing one of the two digits.
the number is equal to 8 times the sum of its digits, therefore:
10x+y = 8(x+y), or
That leaves only one solution: x=7, y=2.
When the number is added to that with the digits reversed, it should add up to 99:
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