A car runs on a highway with an average speed of 80km per hour. After six hours, there is just 60% of the whole journey left How many kilometers is this highway!

A car runs on a highway with an average speed of 80km per hour. After six hours, there is just 60% of the whole journey left How many kilometers is this highway!

The total length of this highway is (80 × 6) / (1-60%) = 1200 km

A train runs for three hours at a speed of 65 kilometers per hour, and then for two hours at a speed of 80 kilometers per hour. How many kilometers per hour on average?

(65 × 3 + 80 × 2) / (3 + 2) = 355 ／ 5 = 71 (km) a: 71 km per hour on average

A car and a truck drive from place a to place B at the same time. When the car reaches 12 o'clock in the whole journey, the truck is 54 kilometers away from place B. continue to drive at this speed. When the car reaches place B, the truck completes 45 kilometers in the whole journey. How many kilometers are there between a and B?

A: the distance between a and B is 90 km

When the car completes half of the journey, the big car is 40 kilometers away from Jiadi
Keep going at this speed. When the car arrives at B, it's a big car. How many kilometers is the distance between a and B

Because the speed didn't change, when the small car arrived at the second place, the big car traveled 3 / 4 of the whole journey, so the speed of the big car was 3 / 4 of that of the small car
So:
40÷（1－1/2×3/4）
=40÷（1－3/8）
=40÷5/8
=40×8/5
=64（km）