Rahul and Mithun travel a distance of 30 km. The sum of their speeds is 70 km/h and the total time taken by both to travel the distance is 2 hours 6 minutes. The difference between their speeds is: |
30 km/h 25 km/h 20 km/h 35 km/h |
30 km/h |
Total time = 2 hours 6 minutes = \(\frac{21 }{10}\) hours Let speed of Rahul = a km/h & Speed of Mithun = ( 70 - a ) km/h Using formula :- Time = \(\frac{Distance }{Speed}\) ATQ, \(\frac{30 }{a}\) + \(\frac{30 }{70 - a }\) = \(\frac{21 }{10}\) hours \(\frac{10 }{a}\) + \(\frac{10 }{70 - a }\) = \(\frac{7 }{10}\) a² - 70a + 1000 = 0 On solving , a = is either 50 km/h or 20 km/h SO , Difference b/w their speed = 50 - 20 = 30 km/h
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