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Two places A and B are 120 km apart on a highway. A car starts from A and another from B at the same time if the car move in the same direction at different speeds they meet in 6 hours if they travel towards Each Other they need in 1 hour 12 minutes find the speed of the two cars. |
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Answer» Answer: Let, speed of car at "a" be x kmph speed of car at "b" be y kmph dis covered by car at "a" in 6 hours = 6x dis covered by car at "b" in 6 hours = 6y Since they are travelling in same direction, sign shouble be negative 6x - 6y = 120 x - y = 20 ------------ (1) 1HR 12 min = 1 12/60 = 72/60 = 6/5 hr Since they are travelling in opposite DIRECTIONS, sign should be positive. (6/5)x + (6/5)y = 120 6x + 6y = 120×5 6x + 6y = 20×5 x + y = 100 ------------ (2) Adding (1) and (2) we get 2x = 120 x = 60 Putting x = 60 in (2) we get y = 40 Therefore,speeds cars are 60 km/h & 40 km/h. |
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