Question

The sum of a two digit number and the number obtained by reversing its digits is 121. Find the number if
its units place digit is greater than the tens place digit by 7

Answer 1

GIVEN :-

• Sum of two digit number and the number obtained by reversing its digits is 121.
• Unit place digit is greater than tens place digit by 7.

TO FIND :-

• The Original Number.

SOLUTION :-

Let the tens place digit be 'x'.

Unit place digit will be 'x+7'.

Original Number → 10x + (x+7)

When we reverse the digits,

Tens place digit will be 'x+7'.

Unit place digit will be 'x'.

Reversed Number → 10(x+7) + x

According to the question, sum of Original number and Reversed Number is 121.

→ 10x + (x+7) + 10(x+7) + x = 121

→ 10x + x + 7 + 10x + 70 + x = 121

→ 22x + 77 = 121

→ 22x = 121 - 77

→ 22x = 44

→ x = 44/22

→ x = 2

____________________

We know ,

Original number → 10x + (x+7)

Putting x = 2,

Original number → 10(2) + 2 + 7

Original number → 20 + 9

Original number → 29

Hence , Original number is 29.