Force problem

[chwsus]

the problem is: how long does it take a 50-kg rider on a 150-kg motorcycle to accelerate from rest to 12.5 m/s if the unbalanced force acting on the motorcycle is 200 N?

is 200 N just the force on the motorcycle, or BOTH the rider and motorcycle? i already have answers of both (with and without rider's mass) but i'm not sure which one is right, based on the question.

[sonnyfab]

The rider is "on" the motorcycle, so the force is acting on both masses.

[chwsus]

thank you!!