Question
A race track is in the shape of a rectangle with length
of 65 metres and area of 9750 m2. A car takes 10 seconds to make one lap around the perimeter of this track. If the car and a person whose speed is 7 m/s, started moving at the same time along the perimeter of the track but in opposite directions, then find the distance between the car and the person, 3 seconds before they cross each other.Solution
Area of the track = length of track x breadth of track = 65 x breadth of track = 9750 So, breadth of track = 9750 ÷ 65 = 150 So, perimeter of the track = (65 + 150) x 2 = 430 metres So, speed of the car = (430/10) = 43 m/s Relative speed of the car with respect to the person = 43 + 7 = 50 m/s So, distance between the car and the person, 3 seconds before they cross each other = 50 x 3 = 150 metres
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