Chapter 9.6, Problem 8P

To determine

Tofind:the total distance, time and speed of upstream and downstream flow.

Answer to Problem 8P

The total distance $\text{600km}$ ,Total time taken $\text{2min5s}$ and average speed $\text{4}\text{.8}\text{m}/\text{sec}$ .

Explanation of Solution

Given:

In a Canoe race Norma travels $\text{300m}$ upstream.

Norma can paddle at a rate of $\text{5}\text{m}/\text{sec}$ in still water.

The rate of the current is $\text{1}\text{m}/\text{sec}$ .

Concept used:

Average speed= $\frac{\text{total distance}}{\text{total time}}$ or $\text{distance=speed}\times \text{time}$ .

  $\text{Time=}\frac{\text{distance}}{\text{speed}}$ .

Calculation:

The race is $\text{300m}$ each way so the distances for both upstream and downstream are $\text{300m}$ .if her rate is $\text{5}\text{m}/\text{sec}$ in still water and the current is $1\text{m}/\text{sec}$ ,then her rate upstream is $5-1=4\text{m}/\text{sec}$ and downs stream is $5+1=6\text{m}/\text{sec}$ .

Use $\text{time=}\frac{\text{distance}}{\text{rate}}$ .

.

	rate	time	distance
upstream	$4$	$75$	$\text{300}$
Downstream	$6$	$50$	$\text{300}$

Total distance is then $\text{300+300=600km}$ .

Total time is then $\text{75s+50s=125s=2min5s}$ .

Average speed= $\frac{\text{total distance}}{\text{total time}}\text{=}\frac{\text{600}}{\text{125}}\text{=4}\text{.8}\text{m}/\text{sec}$ .

Hence, Total distance $\text{600km}$ ,Total time taken $\text{2min5s}$ and average speed $\text{4}\text{.8}\text{m}/\text{sec}$ .