A man can row 28 km/h in still water. If the speed of current is 12 km/h, it takes 15 hours more in upstream than the downstream for the same distance. The distance is?
Answer & explanation
Correct answer: option 2
Speed of man = x, Speed of water = y
x = 25 y = 12
downstream speed (SD) = 28 + 12 = 40 km/h
upstream speed (SU) = 28 - 12 = 16 km/h
SD : SU = 40 : 16
5 : 2
time 2 : 5 ... (Diff. 3 → ×5 → 15)
↓
×5
↓
10 hours
Distance = 40 × 10 = 400 km