3. E有的球是M的两倍, 比F少6个. 在E给M10个球, F给M若干个球以后, 他们的球的数量相等, 求M原来有多少个球. 根据条件  1)E=2M;(2)E=F-6;(3)E-10=F-X=M+10+X; 解出来,得到:M=36; I still don't understand. Can someone help me explain this? sorry I cannot type chinese on my computer. Thanks alot! -- by 会员 stmanga (2011/7/19 12:14:07)
Assume F give M x balls,so we have: E=2M; E+6=F E-10=M+10+X=F-X (equation 1)
using E=2M substitute E in E+6=F F=2M+6 using E=2M, F=2M+6 substitute F and E in equation 1 2M-10=M+10+X=2M+6-X
as 2M-10=2M+6-X, -> X=16 so 2M-10=M+26, ->M=36 |