Question

a certain Number between 10 and 100 is 8 times the sum of its digit and if 45 be subtracted from it the digits Will be reversed. Find the Number

Answer 1

let the number be 10x+y

given

10x+y=8(x+y)

2x-7y=0

and also

10x+y-45=10y+x

9x-9y=45

x-y=5

2x-2y=10

on solving them

-5y=-10

y=2

and thus x=7

and thus the number=10x+y=10*7+2=72