Question

I
1. A car covers the first half of the distance between
two places at 40 km/h and another half at 60 km/h. The
average speed of the car is
(a) 40 km/h
(b) 48 km/h
(c) 50 km/h
(d) 60 km/h [CBSE PMT 901​

Answer 1

Answer:

Explanation:

he average speed is distance/time. Suppose the distance is 120km. The first half of the trip takes 120km / (40 km/hr) = 3 hrs. The second half takes 120/60 = 2 hrs. So the average speed is

(120 km + 120 km) / (3 hrs + 2 hrs) = 48 km/hr

Why can't the average be defined by the average of the speed over each segment— 50 km/hr? You could define it this way, but it's not as useful. Take an extreme case: 120 km/hr for the first half and 2 km/hr for the second? If you average the two speeds, you get 51 km/hr. But that is not a meaningful way to describe a 240 km trip taking 62 hours.

Answer 2

Answer:

48km/h

Explanation:

I hope it will help you