Question

a carpenter has two pieces of lumber. He wants to make a rectangular raised flower bed with a ratio of the length to width to be 7:3. what will the width of the flower bed be if each piece of lumber is 20 feet in length?

Answer 1

This is a proportion problem. When we equal two ratios, we end up with a proportion. In this case, we have:

$\frac{L}{W}=\frac{7}{3}$

Where L is for length and W for width.

We also have that the length is 20, then, we have:

$\frac{L}{W}=\frac{7}{3}\rightarrow\frac{W}{L}=\frac{3}{7}\rightarrow W=\frac{3\cdot L}{7}\rightarrow W=\frac{3\cdot20}{7}$$W=\frac{60}{7},W=8.57142\ldots$

Then, the width is W = 60/7 (or about W = 8.5714 feet).