Question

the sum of the digits of a two-digit number is 10. If 36 is subtracted from the number , the digits interchange their places. Find the number

Answer 1

let the digit a one's place be x and tens be y
x+y=10
y=10-x............[1]
no; 10y+x 
reverse: 10x+y
10y+x-36=10x+y
9y-9x=36
y-x=4
from eq[1]
10-x-x=4
6=2x
x=3 
and y=7
no is 73 

Answer 2

7and 3 is a correct answer