A number consists of two digits whose sum is five. When the digits are

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

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

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.