There is too much information given, it's hard to understand exactly which variables are important in this problem.
Answer:
I think they use it at night because they want to avoid involving themselves in road accident while crossing the street. When there are reflective strips on their clothes, drivers do notice them even at far ends of the street since the strips will reflect the rays from the car lights to the driver,hence, the driver notifies that there is a pedestrian crossing and therefore slows down.
Answer:

Explanation:
Distance is the product of speed and time.

The speed of the car is 75 kilometers per hour. It traveled for 5.5 hours.

Substitute the values into the formula.

Multiply. Note that the hours will cancel each other out.

The car travelled <u>412.5 kilometers.</u>