Question

3) A car covers the 1st half of the distance between two places at a speed of 40 km/hr and the second
at 60 km/hr. The average speed of the car is
a) 100 km/hr
b) 48 km/hr
c) 50 km/hr
d) 25 km/hr​

Answer 1

Answer:

50 km/hr

Explanation:

Average is total/no.of parts

Add the two speed and divide by two.

60 +40 = 100

100/2 = 50 km/ph

Answer 2

Explanation:

Let us consider the total distance travelled by car be x

Time taken to complete the first half distance

t1 = x / (2×40) = x / 80 hour

Now... time taken to complete the second half

t2 = x / (2×60) = x / 120 hour

Therefore, total time taken

t = t1 + t2 = x / 80 + x / 120

= x / 48 hour

And as we know that speed is distance : time

So, Avg speed = x / (x/48)

= 48 km/hr