Marcos

Marcos wants to buy grass seed to cover his whole lawn, except for the pool. The pool is 7 1/2 m by 3 1/4 m. Find the area the grass seed needs to cover. The dimensions of the lawn are 50 m x 150 m.

Correct answer:

A =  7475 m²

Step-by-step explanation:

$$\begin{gathered} x=50\text{m} \\ y=150\text{m} \\ a=7\frac{1}{2}=7+\frac{1}{2}=\frac{7\cdot 2+1}{2}=\frac{14+1}{2}=\frac{15}{2}=7.5\text{m} \\ b=3\frac{1}{3}=3+\frac{1}{3}=\frac{3\cdot 3+1}{3}=\frac{9+1}{3}=\frac{10}{3}\doteq 3.3333\text{m} \\ {S}_1=a\cdot b=\frac{15}{2}\cdot \frac{10}{3}=\frac{15\cdot 10}{2\cdot 3}=\frac{150}{6}=25{\text{m}}^2 \\ {S}_2=x\cdot y=50\cdot 150=7500{\text{m}}^2 \\ A=S_2-S_1=7500-25=7475{\text{m}}^2 \end{gathered}$$

Try another example