Walking at 6/7 of his usual speed, a man is 15 minutes late to his destination. What is his usual time to reach the destination? MCQ with Answer and Explanation

Explanation:
Total path distance = 150 + 100 = 250 meters. Relative speed index in same direction = 56 - 46 = 10 km/h = 10 * (5/18) = 25/9 m/s. Time required = 250 / (25/9) = 250 * 9 / 25 = 90 seconds.

Explanation:
New speed = 4/5 of usual speed => New time = 5/4 of usual time. Difference = 1/4 of usual time = 8 minutes. Usual time = 8 * 4 = 32 minutes.

Explanation:
Let car speed be c, then train speed is 1.2c. Time difference = 120/c - 120/(1.2c) = 10/60 hour = 1/6 hour. 120/c * (1 - 1/1.2) = 1/6 => 120/c * (0.2/1.2) = 1/6 => 120/c * (1/6) = 1/6 => c = 120 km/h.