A:3
B:2 2
C:1+ 2
D:2
--I think it's really necessary. It is reported that the food that Chinese people
every year is enough to feed 200 million people for a year.
甲和乙两人玩“打弹珠”游戏,甲对乙说:“把你珠子的一半给我,我就有10颗珠子”,乙却说:“只要把你的13给我,我就有10颗”,如果设乙的弹珠数为x颗,甲的弹珠数为y颗,则列出方程组正确的是( )