Bài 15
Ta có \(\left\{{}\begin{matrix}A.G=140000\\A+G=750\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}A=\dfrac{140000}{G}\\\dfrac{140000}{G}+G=750\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}G=400\\G=350\end{matrix}\right.\)
TH1: Với G = 400
\(A=350\)
a, \(L=\dfrac{N}{2}.3,4=\dfrac{2A+3G}{2}.3,4=3230\)
b, \(Cx=\dfrac{N}{20}=\dfrac{2A+3G}{20}=95\)
TH2: G = 350 tương tự nhé