求助 數學PP題

susanyaki

Three grades of milk are 1 percent, 2 percent, and 3 percent fat

by volume. If X gallons of the 1 percent grade, Y gallons of the

2 percent grade, and Z gallons of the 3 percent grade are mixed

to give X+Y+Z gallons of a 1.5 percent grade, what is X in terms

of Y and Z ?

1  Y+3Z

2  Y+3 / 4

3  2Y+3Z

4  3Y+Z

5  3Y+4.5Z

答 1

一直搞不懂…….

invisiblewys

0.01x+0.02y+0.03z=0.015(x+y+z)

得出x=y+3z

angelavivi

根据题意列等式:

(1%X+2%Y+3%Z)/(X+Y+Z)=1.5%

化简得出：X+2Y+3Z=1.5X+1.5Y+1.5Z

然后就得出你要的结果了

susanyaki

謝謝大家....嗚感動