A number is divisible by 72 if the given number is divisible by both 8 and 9. Divisible by 8 : If last three digit is divisible by 8, then the given number is also divisible by 8. Divisible by 9 : If the sum of digit is divisible by 9, then the given number is also divisible by 9. Then,
58y
8
⇒y=4 ∵
584
8
=73
1+3+4+x+5+8+y
9
=
21+x+y
9
=
21+x+4
9
=
25+x
9
⇒x=2∵
25+2
9
=
27
9
=3 ∴ The value of x and y is 2, and 4 respectively Then, 2x + y = 2 × 2 + 4 = 8.