Question

Two cars start from a place with a speed of 50 km/hr at an interval of 12 minutes. What is the speed of a man coming from the opposite direction towards the place if he meets the cars at an interval of 10 minutes?

A 12 km/hr Correct Answer Incorrect Answer
B 20 km/hr Correct Answer Incorrect Answer
C 15 km/hr Correct Answer Incorrect Answer
D 5 km/hr Correct Answer Incorrect Answer
E 10 km/hr Correct Answer Incorrect Answer

Solution

Distance covered in 12 minutes at 50 km/hr =50 x (12/60) Distance covered in 10 minutes at (50 + x) km/hr = (10/60) x (50 + x) Now, Distance covered in 12 minutes at 50 km/hr = Distance covered in 10 minutes at (50 + x) km/hr ⇒ 50 x (12/60) = (10/60) x (50 + x) ⇒ 50 x 12 = 500 + 10x ⇒ 600 = 500 + 10x ⇒ 10x = 600 - 500 = 100 ⇒ x = 10 km/hr

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