Flowerbeds

There are three square flower beds on the square grassy plot. What percentage is the grassed part of the land, when one side of the land is 35 m and the side of the flowerbed is 10 m?

Correct answer:

p =  75.5 %

Step-by-step explanation:

$$\begin{gathered} a=35\text{m} \\ b=10\text{m} \\ n=3 \\ {S}_1=b^2=10^2=100{\text{m}}^2 \\ {S}_2=a^2=35^2=1225{\text{m}}^2 \\ p=100\cdot \frac{S_2-n\cdot S_1}{S_2}=100\cdot \frac{1225-3\cdot 100}{1225}=\frac{3700}{49}\%=75.5\% \end{gathered}$$

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