Question

A train travels at a speed of$60km/h$for$0.52hr$, of $30km/h$for the next $0.24hr$ and then at $70km/h$ for the next $0.71hr$. What is the average speed of the train?

Answer 1

Step 1: Calculate the distance for each case

The train travels at a speed of $60km/h$ for a time of $0.52hr$

We know that$Speed=\frac{dis\tan ce}{time}$

Distance $=60x0.52=31.2km————–\left(i\right)$

Now, in the second case,

Distance $=30\times 0.24=7.2km———–\left(ii\right)$

Here in the third case,

Distance $=70\times 0.71=49.7km———–\left(iii\right)$

Step 2: Find the distance and time

Now, combining all the equations (i), (ii) and (iii) and adding we get,

Total distance travelled $=(31.2+7.2+49.7)km=88.1km.$

Total time taken$=(0.52+0.24+0.71)hr=1.47hr.$

Step 3: Find the Average Speed

$Averagespeed=\frac{Totaldis\tan cetravelled}{Totaltimetaken}$

$=\frac{88.1}{1.47}km/hr$

Hence, average speed $=59.9km/hr$.