RRB NTPC · Question 99
Two jeeps run from a house at a speed of 20 km/h at an interval of 10 minutes. How much speed (km/h) will a woman coming from the opposite direction of the house have to run so that she can meet the second jeep at an interval of 6 minutes? A. 13 B. \(13\dfrac{2}{3}\) C. \(13 \dfrac{1}{3}\) D. 13.5
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Answer: (D) C
Explanation
The jeeps are 20 × 10/60 = 10/3 km apart. The woman meets them 6 minutes (1/10 h) apart, so the relative speed is (10/3) ÷ (1/10) = 100/3 km/h. Her speed = 100/3 − 20 = 40/3 = 13 1/3 km/h.