Question

A car running between two points P and Q on a straight path. If it travels half of distance between P and Q with velocity 40 km/h and other half with 60 km/h and return in the same manner. The average speed of the car is
(A) 50 km/h
(B) 52 km/h
(C) 100 km/h
(D) 48 km/h

ANSWER THE QUESTION ASAP WITH EXPLANATION...
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Answer 1

Answer:

Option(D)

Explanation:

Shortcut Method :

Let the distance be 'x'.

Half of distance with 40 km/hr and other with 60 km/hr.

Total distance = 2x.

Total time = x/40 + x/60

Average Speed = Total distance/Total time

=> 2x/(x/40 + x/60)

=> 2x/x/24

=> 48 km/hr

Therefore, distance = 48 km/hr

Hope it helps!

Answer 2

Answer:

(D) 48km/h

Explanation:

let's take half of the distance as 'x'.

Therefore, the total distance is '2x'.

since speed = $\frac{distance}{time}$, speed = $\frac{2x}{\frac{x}{40}+\frac{x}{60} }$

→ $\frac{2x}{\frac{5x}{120} }$ = 48km/hr