SOLUTION
We have been given the formula for distance travelled as
D = RT, where D is the distance, R, is the rate of speed and T is the time, we are told to use the formula to find R.
From D = RT, this means you should make R stand alone, that is the subject. It becomes
[tex]\begin{gathered} D=RT \\ \text{divide both sides of the equation by T, we have } \\ \frac{D}{T}=\frac{RT}{T} \\ \text{cancelling out T we have} \\ \frac{D}{T}=R \\ so\text{ } \\ R=\frac{D}{T} \end{gathered}[/tex]