Question

14．在開展“情系玉樹”的愛心活動(dòng)中，甲同學(xué)捐款的錢數(shù)是乙同學(xué)的$\frac{5}{21}$，丙同學(xué)捐款的錢數(shù)是甲同學(xué)的$\frac{4}{5}$，如果三名同學(xué)共捐款310元，那么乙同學(xué)捐款多少元？

Answer 1

分析 設(shè)乙同學(xué)捐款x元，則甲同學(xué)捐款$\frac{5}{21}$x元，丙同學(xué)捐款$\frac{4}{5}$×$\frac{5}{21}$x元，根據(jù)等量關(guān)系：甲同學(xué)捐款的錢數(shù)+乙同學(xué)捐款的錢數(shù)+丙同學(xué)捐款的錢數(shù)=三名同學(xué)共捐款310元，列方程解答即可．

解答 解：設(shè)乙同學(xué)捐款x元，則甲同學(xué)捐款$\frac{5}{21}$x元，丙同學(xué)捐款$\frac{4}{5}$×$\frac{5}{21}$x元，
x+$\frac{5}{21}$x+$\frac{4}{5}$×$\frac{5}{21}$x=310
     x+$\frac{5}{21}$x+$\frac{4}{21}$x=310
                 $\frac{10}{7}$x=310
                      x=217，
答：乙同學(xué)捐款217元．

點(diǎn)評(píng) 本題考查了分?jǐn)?shù)四則復(fù)合應(yīng)用題，關(guān)鍵是根據(jù)等量關(guān)系：甲同學(xué)捐款的錢數(shù)+乙同學(xué)捐款的錢數(shù)+丙同學(xué)捐款的錢數(shù)=三名同學(xué)共捐款310元，列方程．