Question

The sum of positive integers x and y is 77. What is the value of xy ? (1) x = y + 1 (2) x and y have the same tens digit.

Answer 1

b/q , x+ y = 77 ........... (1)
again given , x= y +1 ......... (2)
putting (2) in (1) ,
y+1 +y = 77
=) 2y +1 = 77
=) 2y = 76
=) y = 38
again from (1) ..
x + 38 = 77
=) x = 39