The speed of the river is 5/3 km / h, the speed of the boat is 15/2 times higher.

| March 15, 2021 | education

The speed of the river is 5/3 km / h, the speed of the boat is 15/2 times higher. How far will the boat sail down the river in 1) 3/20 hours 2) 6 minutes?

Find the boat’s own speed:

5/3 * 15/2 = 5 * 5/2 = 25/2 = 12.5 km / h.

The speed of the boat along the river will be greater than its own by the amount of the current. Let’s find this speed:

12.5 + 5/3 = 25/2 + 5/3 = 75/6 + 10/6 = 85/6 = 14 1/6 km / h.

Find how long the boat will sail downstream in 3/20 hours:

14 1/6 * 3/20 = 85/6 * 3/20 = 17/8 = 2 1/8 km.

Let’s convert minutes to hours:

6 minutes = 6/60 hours = 0.1 hours.

Let’s find how far the boat will sail downstream of the river in 6 minutes:

14 1/6 * 0.1 = 85/6 * 1/10 = 17/12 = 1 5/12 km.

Answer: in 3/20 hours the boat will sail 2 1/8 kilometers down the river, in 6 minutes in the same direction it will sail 1 5/12 kilometers.



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