Question

A kayaker paddles upstream from cam to photograph a waterfall and returns. The kayaker’s speed while traveling upstream is 4 miles per hour. His speed going downstream is 7 miles per hour. What is the kayaker speed still in water? What is the speed of the current?

Answer 1

Hello!

First, let's analyze the exercise and get some important information:

• The kayaker’s speed while ,traveling upstream, is 4 miles per hour.

,

• His speed ,going downstream, is 7 miles per hour.

Let's write it as a system with variables:

• k ,= speed of the kayaker

,

• c, = speed of the current

`\begin{cases}k-c=4 \\ k+c=7\end{cases}`

If we add these two equations, we can cancel C, look:

`\begin{gathered} 2k=11 \\ k=(11)/(2) \\ k=5.5 \end{gathered}`

Now that we know the value of k, let's replace it in the first equation:

`\begin{gathered} k-c=4 \\ 5.5-c=4 \\ 5.5-4=c \\ c=1.5 \end{gathered}`

What is the kayaker speed still in the water? 5.5mi/h

What is the speed of the current? 1.5mi/h