Question

A car travels with speed 30 km h-' for 30 minutes
and then with speed 40 km h-1 for one hour.
Find :
(a) the total distance travelled by the car
(b) the total time of travel, and
(c) the average speed of car ​

Answer 1

Answer:

Speed of car for first 30 minutes = 30 km h^{-1}h

−1

Speed of car for next 1 hour = 40 km h^{-1}h

−1

(a) total distance travelled by the car

First case

Speed = distance / time

distance = speed x time

= 30 x 0.5 ---- (30 min = 0.5 hour)

= 15 km ---- (i)

Second case

speed = 40 km h^{-1}h

−1

distance = 40 km x 1

= 40 km ---- (ii)

Adding (i) and (ii)

Total distance = 15 km + 40 km

= 55 km

(b) total time of travel = 0.5 hr + 1.0 hr = 1.5 hr

(c) average speed = total distance travelled/total time taken

= 5.5 km/ 1.5 hr

= 36.67 km h^{-1}h

−1