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A car travels with speed 30 km h-' for 30 minutesand 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 |
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Answer» 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 |
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