5. (15 points) A train 360 m long, moving at a constant speed, passed a bridge 240 m long in 4 min. Determine the speed of the train.
Answer: $2.5 \frac{M}{c}$

Solution. The speed of the train: $v=\frac{360+240}{4 \cdot 60}=2.5 \frac{\mathrm{M}}{\mathrm{c}}$.