Question

 A car moves with a speed of 10 km/h for half an hour, 20 km/h for one hour and 50 km/h for 2 hours. Calculate the average speed of the car. ​

Answer 1

Step-by-step explanation:

Average speed =

totaltime

totaldistance

The distance covered=30×

2

1

+25×1+40×2

=120km

Time taken=0.5+1+2=3.5h

Hence,

Average speed=

3.5

120

=34.286km

Answer 2

Step-by-step explanation:

Given = •Speed1 = 10km/h , •Speed2 = 20km/h and •Speed3 = 50km/h

Time1 = 1/2hours,Time2= 1hours and Time3= 2hours.

We know that average speed =

$\frac{total \: distance}{total \: time \: taken}$

$\frac{speed1 + speed2 + speed3}{time1 + time2 + time3}$

$\frac{10 + 20 + 50}{ \frac{1}{2} + 1 + 2}$

$\frac{80}{ \frac{1 + 2 + 1}{2} }$

$\frac{80}{ \frac{4}{2} }$

$\frac{80 \times 2}{4 }$

$\frac{160}{4}$

$40km \: per hour$