Question

A number consists of two digits when the number is divided by the sum of its digits the quotient is 7 if 27 is subtracted from the number the digits interchange their places find the number

Answer 1

let one digit number be "x"
" ten " " " y
no. = 10y+x
x+y=27
A.T.Q
10y+x -27=10x+y
10y-y+x-10x=27
9y-9x=27
y-x=3 or -x+y=3
2x=24
x=12
so y=15