xX80%+yX90%=$90.3...(2)
Finally, x=?,y=?
Quick!!!
更新1:
QUICK!!!!!!!!!!!!!!!!!!!!!!!
x+y=$108,xX80%+yX90%=$90.3.
回答 (1)
2009-12-30 10:35 pm
✔ 最佳答案
x+y=$108 ....(1)xX80%+yX90%=$90.3...(2)
By(1) :
x = 108 - y , sub it to (2) :
(108 - y)(80%) + y(90%) = 90.3
108*0.8 - 0.8y + 0.9y = 90.3
0.1y + 86.4 = 90.3
0.1y = 3.9
y = 39
sub it to (1):
x + 39 = 108
x = 69
收錄日期: 2021-04-21 22:06:29
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20091230000051KK00926