Answer:
32.5 m/s
Step-by-step explanation:
The total momentum must be conserved before and after the collision:

where
m_c = 300 kg is the mass of the car
m_t = 600 kg is the mass of the truck
u_c = 60 m/s is the initial velocity of the car
u_t = 10 m/s is the initial velocity of the truck
v_c = 15 m/s is the final velocity of the car
v_f is the final velocity of the truck
Solving for v_f, we find:
