the speed of boat in still water is 15km/ hr . it can go 30 km upstream and return down stream to the original point in 4hr 30min.find the speed of the stream
Answers
Answer:
Speed of stream = 5 km/Hr
Step-by-step explanation:
Let say speed of stream = S Km/Hr
Speed of Boat in still water = 15 km/Hr
Speed Upstream = (15-S) km/Hr
Speed Down Stream = (15+S) Km/Hr
Distance upstream = 30 km
Time take upstream = 30/(15-S) Hr
Distance Downstream = Distance upstream = 30 km
Time taken Downstream = 30/(15+S) Hr
Total time take = Time upstream + Time Downstream
4 hr 30 mins = 9/2 Hrs
9/2 = 30/(15-S) + 30/(15+S)
(9/2)(15-S)(15+S) = 30 (15 +S + 15 - S)
9 (225 - S²) = 2×30 × 30
225 -S² = 200
S² = 25
S = 5 km/Hr
Speed of stream = 5 km/Hr
Answer:
Speed of stream = 5 km/Hr
Step-by-step explanation:
Let say speed of stream = S Km/Hr
Speed of Boat in still water = 15 km/Hr
Speed Upstream = (15-S) km/Hr
Speed Down Stream = (15+S) Km/Hr
Distance upstream = 30 km
Time take upstream = 30/(15-S) Hr
Distance Downstream = Distance upstream = 30 km
Time taken Downstream = 30/(15+S) Hr
Total time take = Time upstream + Time Downstream
4 hr 30 mins = 9/2 Hrs
9/2 = 30/(15-S) + 30/(15+S)(9/2)(15-S)(15+S) = 30
(15 +S + 15 - S)9 (225 - S²) = 2×30 × 30225 -S² = 200S² = 25 S = 5 km/Hr
Speed of stream = 5 km/Hr