A private van tracks at 40 km/h for 4 hours and then steps up to 60 km/h for the next 2 hours. Find the mean average speed. MCQ with Answer and Explanation

Explanation:
New speed = 300 / 4 = 75 km/h. Since new speed is original speed + 15 km/h, original speed = 75 - 15 = 60 km/h.

Explanation:
By 8 AM, the first man has traveled for 2 hours, covering 4 * 2 = 8 km. Relative speed = 6 - 4 = 2 km/h. Time taken to meet = 8 / 2 = 4 hours. Distance from A = Speed of second man * Time = 6 * 4 = 24 km.

Explanation:
Downstream speed = 1 km / (5/60 hours) = 12 km/h. Upstream speed = 1 km / (12/60 hours) = 5 km/h. Speed of stream = (Downstream speed - Upstream speed) / 2 = (12 - 5) / 2 = 3.5 km/h.