Question

A car travels certain distance at a speed of 30 km/hr and returns with a speed of 10m/s calculate the average speed of the car​

Answer 1

Explanation:

Distance = Velocity X Time. In symbols, D=V T, implying V=D/T, so Average speed = (total distance)/(total time). Call “t” the total time, “t1” the time going to the destination at v1 = 30 km/h and “t2” the return time at v2=20 km/h. Call “d” the one-way distance, so 2d = total distance. From D=V T we have T=D/V, so t = t1+t2 = d/v1 + d/v2. Put this together to get Average speed = 2d/(d/v1 +d/v2).

You can use this formula with any choice you want for d, such as 1 km, because it doesn’t affect the answer, or just divide d from the numerator and denominator to get

Average speed = 2/(1/v1 + 1/v2) = 2 v1 v2/(v1+v2) = 24 km/h

Answer 2

$\huge\star\underbrace{\tt Answer}\star$

33km/h

Explanation:

Speed(1) = 30km/h, Speed(2) = 36km/hr (1 m/sec = 3.6km/h)

$\mathrm{Average\: speed = \frac{30+36}{2} = \frac{66}{2} = 33km/h}$