Solve the following word problems.

A two digit number and the number with digits interchanged add up to 143. In the given number the digit in unit’s place is 3 more than the digit in the ten’s place. Find the original number.

Let the digit in unit’s place is x

and that in the ten’s place is y

The number obtained by interchanging the digits is

According to first condition two digit number + the number obtained by interchanging the digits = 143

From the second condition,

digit in unit’s place = digit in the ten’s place + 3

Adding equations (I) and (II)

Putting this value of x in equation (I)

x + y = 13

The original number is 10