Question

A car moves with a speed of 30 km/h-1 for half an hour;25 km/h-1 for one hour and 40 km/h-1 for two hours.calculate the average speed of the car​

Answer 1

• Speed = 30 km/hr

Time = 1/2 hr

Distance = 30 × 1/2

= 15 km

• Speed = 25 km/hr

Time = 1 hr

Distance = 25 × 1

= 25 km

• Speed = 40 km/hr

Time = 2 hr

Distance = 40 × 2

= 80 km

$average \: speed = \frac{total \: distance \: covered}{total \: time \: taken}$

$= \frac{15 + 25 + 80}{ \frac{1}{2} + 1 + 2 }$

$= \frac{120}{ \frac{7}{2} } = \frac{240}{7}$

=34.28 km /hr