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1. The respective ratio between the speed of a speed of the car, bus and train is 72 km/hr together. What is the average speed (km/h)of the car and the train together?
- A. 82
- B. 82
- C. 82
- D. 82
Answer: Option D
Explanation:
Let the speeds of the car, train and bus be 5x, 9x and 4x km/hr respectively.
Average speed = (5x + 9x + 4x)/3 = 18x /3 = 6x km/hr.
Also, 6x = 72 = > x = 12 km/hr
Therefore, the average speed of the car and train together is = ( 5x + 9x)/2 = 7x = 7 x 12 = 84 km/hr.
Average speed = (5x + 9x + 4x)/3 = 18x /3 = 6x km/hr.
Also, 6x = 72 = > x = 12 km/hr
Therefore, the average speed of the car and train together is = ( 5x + 9x)/2 = 7x = 7 x 12 = 84 km/hr.
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