Question

The sum of a two digit number is 15. The number obtained by intrchanging its digits exceeds the givn number by 9 Find the original number.

Answer 1

Let us assume, x and y are the two digits of the two-digit number.

Therefore, the two-digit number = 10x + y and reversed number = 10y + x

Given:

x + y = 15 --------------1

Also given:

10y + x = 10x + y + 9

9y - 9x = 9
y - x = 1 --------------2

Adding equation 1 and equation 2

2y = 16
y = 8

Therefore, x = 15 - y = 15 - 8 = 7

Therefore, the original two-digit number = 10x + y = 10 * 7 + 8 = 78