题目
In rectangle A, the ratio of the length to the width is 3: 1. In rectangle B, the ratio of the length to the width is 4: 1. The area of rectangle A is 27 percent of the area of rectangle B. The perimeter of rectangle A is v percent of the perimeter of rectangle B.
选项
C.The two quantities are equal.
D.The relationship cannot be determined from the information given.
解析
在矩形\(A\)中,长与宽的比例为\(3:1\)。在矩形\(B\)中,长与宽的比例为\(4:1\)。矩形\(A\)的面积是矩形\(B\)面积的\(27\%\)。矩形\(A\)的周长是矩形\(B\)周长的\(v\%\)。设矩形\(A\)的宽为\(x\),则长为\(3x\),其面积\(S_{A}=3x\times x = 3x^{2}\),周长\(P_{A}=2\times(3x + x)=8x\)。
设矩形\(B\)的宽为\(y\),则长为\(4y\),其面积\(S_{B}=4y\times y=4y^{2}\),周长\(P_{B}=2\times(4y + y) = 10y\)。
已知\(S_{A}=0.27S_{B}\),即\(3x^{2}=0.27\times4y^{2}\)
\[
\begin{align*}
3x^{2}&=1.08y^{2}\\
x^{2}& = 0.36y^{2}\\
x&=0.6y
\end{align*}
\]
将\(x = 0.6y\)代入\(P_{A}\)和\(P_{B}\)中计算\(v\)的值。
\(P_{A}=8\times0.6y = 4.8y\),\(P_{B}=10y\)
因为\(P_{A}=v\%\times P_{B}\),即\(4.8y=\frac{v}{100}\times10y\)
\[
\begin{align*}
4.8y&=\frac{v}{10}y\\
v&=48
\end{align*}
\]
由于\(48<54\),所以\(v < 54\),即\(Quantity\ B\)更大,答案是\(B\)