A car covers a certain distance at a speed of 48 km/h in 50 minutes. With what speed should it run to decrease the time of journey by 10 minutes? MCQ with Answer and Explanation

Explanation:
Total path distance = 140 + 110 = 250 meters. Relative speed index in same direction = 52 - 42 = 10 km/h = 10 * (5/18) = 25/9 m/s. Time required = 250 / (25/9) = 250 * 9 / 25 = 10 * 9 = 90 seconds.

Explanation:
Time = 3 hours 20 minutes = 3 + 20/60 = 3.333 hours = 10/3 hours. Speed = Distance / Time = 240 / (10/3) = 240 * 3 / 10 = 72 km/h.

Explanation:
Time difference = 15 - (-5) = 20 minutes = 20/60 = 1/3 hours. Let distance be d. d/30 - d/40 = 1/3 => (4d - 3d)/120 = 1/3 => d/120 = 1/3 => d = 40 km.