100 cars on one lane road. when a faster car meets slower car, it travels at slower car's rate.

Answer

When 100 cars are on one lane and the faster car of the lane meets the slower car then the rate of the movement of the vehicle is decided by the slowest moving car.

The flow rate of traffic is the rate of the vehicle car a point in the given interval of time.

When the car is moving slowly fast-moving cars will not get the chance to move and they have to follow the slow-moving car.

Hence, it is rightly stated the flow of traffic is decided by slow-moving vehicles.

this would be about 43%