Question

The sum of the digits of 2-digits number is 7. If the digits are reversed ,the new number is equal to 3 less than 4 times the original number find

Answer 1

let x be the tens digit and y be the unit digit

Original Number=10x + y

x + y=7 (given)...........................................................eq1

Reverse Number=10y + x

10y + x = 4(10x + y) - 3 (given)

10y + x = 40x + 4y - 3

39x - 6y = 3

13x - 2y = 1..................................................eq2

After solving eq1 and eq2, we get

x = 1 , y = 6

So,Original number=16

New Number=61