Question

A car covers half the distance at a speed of 50 km/h and the other half at 40 km/h. Find the average speed of the car.

Answer 1

Let the total distance = x km.

First half is covered with a speed of 50 km/h.

∴ Time taken to cover first half of the distance (t₁) = \(\frac{\frac{x}{2}}{50}= \frac{x}{100} \,km\)

Second half is covered with a speed of 40 km/h .

∴ Time taken to cover second half of the distance (t₂) = \(\frac{\frac{x}{2}}{40} = \frac{x}{80} \,km\) 

Total time =t₁+ t₂ = \(\frac{x}{100} \,+\,\frac{x}{80}= \frac{9x}{400}\)

Average speed of the car = \(\frac{Total\, distance}{Time}= \)