In order to qualify for the finals in a racing event, a race car must achieve an average speed of 250 km//h?

Question

on a track with a total length of 1600 m. If a particular car covers the first half of the track at an average speed of 230 km/h, what minimum average speed must it have in the second half of the track in order to qualify?

Answer 1

250km/hr = 69.44m/s average speed.

This means the car must cover the 1600m track in:

1600/69.44 = 23.04seconds.

The car has coverd 800m at average speed 230km/hr = 63.88m/s

It did the 800m in 800/63.88 = 12.52seconds

The car must therefore cover the remaining 800m in 23.04-12.52 = 10.52 seconds

800m in 10.52 seconds = 76.05m/s = 273.76 km/hr average speed for the second half of the track.