Question

7 times a two digit number is equal to 4 times the digit number obtained by reversing the order of digit if the difference of the digit is 3 find the number

Answer 1

let unit place be x
tenth place be y

therefore number be 10y+x

given x-y = 3 -------(1)

also

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

70y + 7x = 40x + 4y

40x - 7x = 70y - 4y

33x = 66y

x = 2y

putting this value in eq 1

2y - y = 3
y = 3

x =6

so the number is 36