Question

Two cars are doing a race around a 20-km track. They start from the same place at the same time. The speed of first car is 60 km/h, speed of second car is 80 km/h. How long will it take second car to lap the first car?

Answer 1

1 hour

Explanation:

The second car will lap the first car when it has traveled a distance equal to the track length farther than the first car in the same time.

__

The track length is 20 km, so the second car needs to travel 20 km farther than the first.

The difference in rates is 80 km/h -60 km/h = 20 km/h. This means the second car will travel 20 km farther than the first in each hour they race.

The second car will lap the first car after 1 hour.