Question

a car moves with a speed of 30 km/ h for half an hour 25 km / h for one hour and 40 km/ h for two hourz . calculate the average speed of the car
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Answer 1

Answer:

34.28km/hr

Explanation:

Distance covered in half an hour at 30km/hr = s×t = 30×1/2=15km.

Distance coveted in 1hr at 25km/hr= s×t= 25×1 =25km.

Distance covered in 2 hrs at 40km/hr=s×t= 40×2=80km

Therefore, total distance covered= 15+25+80=120km

Total time taken= 3hrs and 30 mins=7/2 hrs.

Therefore, average speed=total distance covered/total time taken = 120×2/7 = 34.28km/hr

Answer 2

Answer:

speed=30km/h

time=0.5hrs

distance=s*t

=15km

speed=25km/h

time=1hrs

distance=s*t

=25km

speed=40km/h

time=2hrs

distance=s*t

=80km

average speed= total distance/total  

time taken

= (15+25+80)/(1+2+0.5)

= 120/3.5

= 34.28km/h.

Explanation: