# How do I calculate this?

1. Sep 16, 2007

### ella_101

“if a cyclist travels at an average speed of 3m/s-1 and turns home at an average speed of 9m/s than what is the average speed of the whole journey?”

do I need an equation to work this out?

Thanks

2. Sep 16, 2007

### lylos

Try using the equations:

$$\bar{speed} = \frac{\Delta X}{\Delta t}$$
$$X = V_0{}t + at$$

Also, try using different values for X.