Seven times a two digit number is equal to four times the number obtained by reversing the order of the digit. If the sum of the digit is 9, fin the number

Seven times a given two digit number is equal to four times the number obtained by inter changing the digits
7(10x+y)=4(x+10y)
70x+7y=4x+40y
66x-33y=0
2x-y=0
2x=y
The sum of the digits is 9
y+x=9
2x+x=9
3x=9
x=3
y=6
that number is 36.