Question

In the following exercise solve$\frac{s}{s+20}=\frac{3}{7}$

Short answer

The solution is$s=15$

Step-by-step solution

Step 1. Given information

$\frac{s}{s+20}=\frac{3}{7}$

Step 2. solve 

Multiply both sides by LCD.

$$\begin{gathered} \left(s+20\right)\left(7\right)\left(\frac{s}{s+20}\right)=\left(s+20\right)\left(7\right)\left(\frac{3}{7}\right) \\ 7s=3s+60 \\ 4s=60 \\ s=15 \end{gathered}$$