Question

Julia traveled 360 kilometers to get to underground caves . On her way home , she traveled twice as fast . What was Julia's average speed on the way to the caves and on the way back home if the total time was 10 hours ?

Answer 1

Let x be the time Julia traveled on her way to the caves ( in hours), then

$x+\frac{1}{2}x=10hours\text{ }$

solving for x we get:

$\begin{gathered} \frac{3}{2}x=10\text{hours} \\ x=\frac{20}{3}\text{hours} \end{gathered}$

Now, we use the formula of the average speed for the speed on the way to the caves:

$AS=\frac{360}{\frac{20}{3}}\frac{\operatorname{km}}{h}$

Therefore, the average speed on her way to the caves was 54 km/h.

Doing the same ( but the time being 1/2 x) for the average speed on her way back home we get 108 km/h.