Aniket swims at the rate of 10 km/hr downstream and 8 km/hr upstream

1.	Aniket swims at the rate of 10 km/hr downstream and 8 km/hr upstream. Find the ratio of the speed of stream to speed of the boat in still water.1. 9 : 12. 1 : 93. 6 : 14. 1 : 6
Answer» Correct Answer - Option 2 : 1 : 9 Given: Upstream speed = 8 km/hr Downstream speed = 10 km/hr Formula Used: Speed = Distance/Time D = B + S U = B - S where, D → Downstream speed, U → Upstream speed, B → Speed of boat in still water, S → Speed of stream. Calculations: D = B + S ⇒ B + S = 10 ----(1) Similarly, U = B - S ⇒ B - S = 8 ----(2) Using componendo-dividendo, we get (B + S) + (B - S)/(B + S) - (B - S) = (10 + 8)/(10 - 8) ⇒ B/S = 9/1 ⇒ B : S = 9 : 1 ∴ The ratio of speed of stream to speed of boat in still water is 1 : 9

Aniket swims at the rate of 10 km/hr downstream and 8 km/hr upstream. Find the ratio of the speed of stream to speed of the boat in still water.1. 9 : 12. 1 : 93. 6 : 14. 1 : 6

Answer» Correct Answer - Option 2 : 1 : 9

Given:

Upstream speed = 8 km/hr

Downstream speed = 10 km/hr

Formula Used:

Speed = Distance/Time

D = B + S

U = B - S

where, D → Downstream speed, U → Upstream speed, B → Speed of boat in still water, S → Speed of stream.

Calculations:

D = B + S

⇒ B + S = 10 ----(1)

Similarly, U = B - S

⇒ B - S = 8 ----(2)

Using componendo-dividendo, we get

(B + S) + (B - S)/(B + S) - (B - S) = (10 + 8)/(10 - 8)

⇒ B/S = 9/1

⇒ B : S = 9 : 1

∴ The ratio of speed of stream to speed of boat in still water is 1 : 9

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