Originally posted by knptmug at 2005-4-20 09:47 PM:& H2 P! U% x+ }0 r0 n
set small watermelon: x, middle watermelon y and big watermeton z 6 a- U+ x1 I* m9 m/ F/ Y- j) H$ e# s# v* n. F
two simultaneous equations are set up:5 n( |2 q4 y* g; ^6 L P' q
0.5x+2y+5z=50 (1)/ x. R% n/ i @0 `$ }( z2 x1 m
x+y+z=50 (2)% l4 [2 R3 J; A8 c
Equation(1) means that the total amount paid is equal t ...