Originally posted by knptmug at 2005-4-20 09:47 PM:+ q/ U$ |& p% w5 U {! C
set small watermelon: x, middle watermelon y and big watermeton z # C2 h0 m, c7 R2 C9 W1 Q4 H( f/ l' R; Y7 m+ ` u4 |; x
two simultaneous equations are set up: 2 u' s% K% P. \. \ C/ r& y$ Y: T0.5x+2y+5z=50 (1)0 ]! M0 |/ G" `) S; U
x+y+z=50 (2) ! ? Q: h: M% |$ y1 j3 XEquation(1) means that the total amount paid is equal t ...