Question

The digits of a two-digit number differ by 3. If the digits are interchanged, and the resulting number is added to the original number, we get 143. What can be the original number?

Answer 1

Let us assume, the x is the tenth place digit and y is the unit place digit of the two-digit number. Also assume x > y

Therefore, the two-digit number is 10x + y and reversed number is 10y + x
Given:

x - y = 3 ---------------1

Also given:

10x + y + 10y + x = 143
11x + 11y = 143
x + y = 13 ---------------2

Adding equation 1 and equation 2

2x = 16
x = 8

Therefore, y = x - 3 = 8 - 3 = 5

Therefore, the two-digit number = 10x + y = 10 * 8 + 5 = 85

Answer 2

Let the unit digit be x

Tens digit => x+3

10(x+3)+x

digits interchanged =10x+x+3

10(x+3)+x+10x+x+3=143

=> 10x+30+12x+3=143

=> 22x+33=143

22x=143−33

22x=110

x=11022

x=5

Original number = 85