Question

Dave can hike on level ground 3 miles An hours faster then he can on uphill terrain. Yesterday, he hiked 36 miles, spending 2 hours on level ground and 5 hours on uphill terrain. Find his average speed on level ground?

Answer 1

The Solution:

Let the average speed in uphill level be x and that of the level ground be x + 3.

`36=2(x+3)+5x`
`\begin{gathered} 36=2x+6+5x \\ 36=7x+6 \\ 36-6=7x \\ 30=7x \\ x=(30)/(7)miles\text{ /}hr \end{gathered}`

Find the average speed on level ground.

`3+x=3+(30)/(7)=(21)/(7)+(30)/(7)=(51)/(7)=7(2)/(7)miles\text{ /}hr`

Answer:

`7(2)/(7)\text{ }miles\text{/hr}`