Question

A train has a speed of 60 km/hr for the first one hour and 40 km/ hr for the next half hour . Its average speed in km/hr is ? give the solution

Answer 1

Distance travelled in 1hr=60×1=60 km Distance travelled in half hour= 40×1/2 =20 km Total distance = 60+20=80 km And total time taken = 1hr 30 min Average speed =total distance ÷total time = 80÷3/2=80×2÷3 =160÷3=53.34 km/ hr

Answer 2

The average speed is 53.3 km/hr

Given:

First hour, speed of the train = 60 km/hr

Next half an hour, Speed = 40 km/hr

Solution:

To calculate the average speed for the travel journey, we need total distance traveled and total time for the travel.

The time taken is one hour and half hour, i.e., t = 60 + 30 = 90 min

$\Rightarrow$ t = 3/2 hr

Total distance = d1 + d2

d1 = speed × time → d1 = 60 × 1 = 60 km

d2 = speed × time → d2 = 40 × (1/2) = 20 km

$\Rightarrow$ Total distance d = 60 km + 20 km = 80 km

$Average \ speed = \frac{Total \ distance}{Total \ time}$

$= \frac{80}{\frac{3}{2}}$

$=80\times\frac{2}{3}$

$\Rightarrow$ Average speed = 53.3 km/hr