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2 years ago

5

Burt and ned paddle their canoe 10 miles upstream and 5 miles downstream in 7 hours. if they can paddle 4 mph in calm water, how

fast is the current?

1 answer:

mel-nik [20]2 years ago

6 0

The current flow is 2.4mph.

To find the answer, we have to know about the streamline flow.

<h3>How to find the rate of flow of current?</h3>

The boat's speed will reduce by V miles per hour if it is moving upstream because the current, which moves at a speed of V miles per hour, will be pressing against it. The boat moves downstream at a pace of Vp-V miles per hour as a result. However, if the boat is moving downstream, the current will be pushing it faster, increasing the boat's speed by V miles per hour. The boat's downstream speed as a result is Vp+V miles per hour.

where; Vp is the paddling speed in calm water.

It is given that, upstream distance is 10 miles, and downstream is 5 miles in 7 hours.
Thus, the time taken for downstream is,

$t_d=\frac{S_d}{v_d}=\frac{5}{4+V}$ , where; S is distance and v is speed.

Similarly, the time taken for upstream is,

$t_u=\frac{S_u}{v_u}=\frac{10}{4-V}$

The total time taken is,

$t=7hours=t_d+t_u\\$

From this, the velocity of current is,

$\frac{5}{4+V}+\frac{10}{4-V} =7\\\\V=2.4mph$

Thus, we can conclude that, the current flow is 2.4mph.

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