Civil Services Examination · ಪ್ರಶ್ನೆ 13

A toy T jumps forward or backward. In each forward jump it moves 5' forward whereas in each backward jump it moves 2' backward. If in 31 jumps T moves exactly 15' forward, then what is the difference of the number of forward and backward jumps?

1. A6
2. B7
3. C8
4. D9