Question

7 times a two digit number is equal to 4 times the two digit number with the digits reversed. Find the number if the sum of the digits is 3

Answer 1

let x be unit place of a number

y be tenth place of a number

so number is 10y + x

it's reverse is , 10x + y

according to given condition ,

7 ( 10y + x ) = 4 ( 10x + y )

70y + 7x = 40x + 4y

66y = 33x

2y = x

but

x + y = 3

so

2y + y = 3

3y = 3

y = 1

so x = 2

number is , 12