A scooter travels from town P to town Q at 30 km/h and returns at 45 km/h. Find the net average speed for the round journey. MCQ with Answer and Explanation

Explanation:
Original speed = 10 km / (12/60 hours) = 50 km/h. New speed = 50 - 5 = 45 km/h. New time = 10 / 45 hours = 2/9 hours = (2/9) * 60 minutes = 40/3 minutes = 13 minutes 20 seconds.

Explanation:
New speed = 6/7 of usual speed => New time = 7/6 of usual time. Difference = 1/6 of usual time = 15 minutes. Usual time = 15 * 6 = 90 minutes.

Explanation:
Let the speeds be 5x, 9x, and 4x. Average speed of all three = (5x + 9x + 4x) / 3 = 18x / 3 = 6x = 60 km/h => x = 10. Speed of car = 50 km/h, speed of bus = 40 km/h. Average speed of car and bus = (50 + 40) / 2 = 45 km/h.