Question

7 times a two digit number is the same as four times the number obtained on interchanging the digits of the given number. if one digit of the given number exceeds the other by 3, find the number

Answer 1

36 is the answer
7(10x +y)=4(10y+x)
y=x+3
7(10x +x+3)=4(10x(x+3)+x)
77x +21=44x+120
33x=99
x=3
y=6