A number consists of two digits whose sum is five. When the digits are reversed, the number becomes greater by nine. Find the number.

Question

Philoid · Accepted Answer

Let the one’s digit be ‘a’ and ten’s digit be ‘b’

Given, number consists of two digits whose sum is five. When the digits are reversed, the number becomes greater by nine.

⇒ a+ b = 5 ----- (1) and

10a + b – (10b + a) = 9

⇒ a – b = 1 ------ (2)

Adding (1) and (2)

Thus, 2a = 6

⇒ a = 3

∴ b = 2

Number is 23.