Question

1. A car covers the first half of the distance between two places at a speed of 40 km/hr. and
the second half at 60 km/hr. The average speed of the car is
(a) 48 km/hr (b) 50 km/hr (c) 45 km/hr (d) 47.5 km/hr​

Answer 1

Answer:

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Answer 2

car covers the first half of the distance between two places at a speed of

40km/hr and second half at 60 km/hr . calculate the average speed of the car

:

let a = average speed for the trip

let d = half the distance

:

write a time equation, time = dist/speed

d%2F40 + d%2F60 = %282d%29%2Fa

we don't need d, divide thru by d and you have

1%2F40 + 1%2F60 = 2%2Fa

multiply by 120a to clear the denominators, results:

3a + 2a = 120(2)

5a = 240

a = 240/5

a = 48 km/hr