Question

There is a number between 10 and 100. The number is 8 times the sum of its digit.If 45 is subtracted from it , the result is number formed by interchanging its digit.Find the number.

soln

Let the number be x , let the sumb be y
8x= y
so 8x/y - 45 = yx

Answer 1

I think you will have better luck working with the digits.

Let the number have the digits xy
So, its value is 10x+y. Now we have

10x+y = 8(x+y)
10x+y-45 = 10y+x

Now you can easily discover that the number is 72