题目《九章算术》中记载:"今有甲乙二人持钱不知其数.甲得乙半而钱五十,乙得甲太半而亦钱五十.问:甲、乙持钱各几何?"大意是:甲、乙二人带着钱,不知是多少,若甲得到乙的钱数的12\frac{1}{2}21,则甲的钱数为505050;若乙得到甲的钱数的23\frac{2}{3}32,则乙的钱数也能为505050,问甲、乙各有多少钱?设甲持钱为xxx,乙持钱为yyy,可列方程组为( )A.{x+23y=50y+12x=50\left\{\begin{array}{l}{x+\frac{2}{3}y=50}\\{y+\frac{1}{2}x=50}\end{array}\right.{x+32y=50y+21x=50B.{x+12y=50y+23x=50\left\{\begin{array}{l}{x+\frac{1}{2}y=50}\\{y+\frac{2}{3}x=50}\end{array}\right.{x+21y=50y+32x=50C.{x−12y=50y−23x=50\left\{\begin{array}{l}{x-\frac{1}{2}y=50}\\{y-\frac{2}{3}x=50}\end{array}\right.{x−21y=50y−32x=50D.{x−23y=50y−12x=50\left\{\begin{array}{l}{x-\frac{2}{3}y=50}\\{y-\frac{1}{2}x=50}\end{array}\right.{x−32y=50y−21x=50知识点:由实际问题抽象出二元一次方程组章节:方程与不等式 / 二元一次方程组