Question
The average speed of a car, a bus and a train together
is 117 km/hr. andn ratio of their speed is 2 :4: 7. What is the average speed of a train and the bus together?Solution
The ratio of speed of the car, bus and train = 2x: 4x: 7x So ATQ, (2x+ 4x + 7x)/3 = 117 2x + 4x + 7x = 117 `xx` 3 13x = 117 `xx` 3 x = 27 km Average speed of the train and the bus = (27`xx` 4+27`xx` 7)/2 = `(108+189)/2` = 148.5 km/hr
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