Question

We drive at a speed of 20 km/h for 3 hours. Then we drive 4 hours at 30 km/h. Calculate our average speed.

Answer 1

A. T. Q

Total distance travelled by total time taken

speed = Total distance / Total timeAverage

Here Total distance travelled is 20 + 40 = 60 km by the car

total time taken is 1 + 3 = 4 hours

here the average speed of the car is given by

S=60/4=15km/hr

this is answer by the question

Answer 2

First speed = 20km/h

Time = 3 hours

Distance = 3×20

= 60 km

Second speed = 30km/h

Time = 4 hours

Distance = 4×30

= 120 km

Total distance = 60+120 = 180km

Total time = 3+4 = 7 hours

Average speed = 180/7

= 25.71 km/h

Hope this will help...