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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: cho A:B=3:5, B:C=7:11, C:D=2:3, A+B+C+D=1161. tìm B

Toán Lớp 8: cho A:B=3:5, B:C=7:11, C:D=2:3, A+B+C+D=1161. tìm B

Comments ( 1 )

  1. Giải đáp:
    $B=210.$
    Lời giải và giải thích chi tiết:
    $\dfrac{A}{B}=\dfrac{3}{5} \Rightarrow A=\dfrac{3}{5} B\\ \dfrac{B}{C}=\dfrac{7}{11} \Rightarrow C=\dfrac{11}{7} B\\ \dfrac{C}{D}=\dfrac{2}{3} \Rightarrow D=\dfrac{3}{2} C=\dfrac{3}{2}.\dfrac{11}{7} B=\dfrac{33}{14} B\\ A+B+C+D=1161\\ \Leftrightarrow \dfrac{3}{5} B+B+\dfrac{11}{7} B+\dfrac{33}{14} B=1161\\ \Leftrightarrow \dfrac{387}{70} B=1161\\ \Leftrightarrow B=210.$

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222-9+11+12:2*14+14 = ? ( )

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