Question

a number consists of two digits whose sum is 8. if 18 is added to the numerator its digit are reserved . find the number

Answer 1

Let number be 10x  +y

So, x+y = 8

Again, 10x + y + 18 = 10y +x
or, 9x - 9y = -18
or, x - y = -2

So, 2x = 6
or, x = 3

So, y 8-3 = 5

So, number is 35

Answer 2

Let number be 10x  +y

So, x+y = 8

Again, 10x + y + 18 = 10y +x

or, 9x - 9y = -18

or, x - y = -2

So, 2x = 6

or, x = 3

So, y 8-3 = 5

So, number is 35