Question

a scale drawing of a school bus has a scale of $\frac{1}{2}$ inch to 5 feet. if the length of the school bus is 4 inches on the scale drawing, what is the actual length of the bus?
10 feet
20 feet
30 feet
40 feet

Explanation:

Step1: Set up proportion

Let $x$ be the actual length of the bus. The scale is $\frac{1}{2}$ inch to 5 feet, and the length on the scale - drawing is 4 inches. So the proportion is $\frac{\frac{1}{2}}{5}=\frac{4}{x}$.

Step2: Cross - multiply

Cross - multiplying gives $\frac{1}{2}x = 4\times5$.

Step3: Simplify the right - hand side

$4\times5 = 20$, so $\frac{1}{2}x=20$.

Step4: Solve for $x$

Multiply both sides of the equation by 2 to get $x = 40$.

Answer:

40 feet