A vessel tracks upstream at 10 km/h and downstream at 18 km/h. Find the net speed of the river current. MCQ with Answer and Explanation

Explanation:
New speed = 5/7 of usual speed => New time = 7/5 of usual time. Difference = 2/5 of usual time = 12 minutes. 1/5 of usual time = 6 minutes => Usual time = 6 * 5 = 30 minutes.

Explanation:
Downstream speed = 48 / 4 = 12 km/h. Upstream speed = 24 / 4 = 6 km/h. Speed in still water = (Downstream speed + Upstream speed) / 2 = (12 + 6) / 2 = 9 km/h.

Explanation:
New speed = 300 / 5 = 60 km/h. Since new speed is original speed + 10 km/h, the original speed = 60 - 10 = 50 km/h.