Question

10. A car travels 30 km at a uniform speed of 40 km/h and next 30 km at a uniform speed of 20 km/h. Its average speed is (A) 30 km/h (B) 32 km/h (C) 2 26 km / h 3 (D) 3 28 km / h 4

Answer 1

Explanation:

for car A :

distance = 30km

speed = 40km/h

then, Time = 3/4h

for car B:

distance = 30km

speed = 20km/h

then, Time = 3/2h

Average speed = Total distance / Total time

=. Total distance = 30+30 = 60km

= Total time = 3/4 + 3/2 = 9/4

Average speed = 60 × 4/9

= 20 × 4/3

= 80/3

= 26.66km/h

I hope that is correct....