數學題SOS....................

某商店以$4000買入5000個橙,他收每個$1.2售出4000個,其餘以成本的6折售出.
A.問他共得多少錢?
成本為 4000/5000 = $0.8
成本6折 = 0.8x0.6 = 0.48
4000x1.2 + (5000-1000)x0.48
= 5280

B.求盈利百分率.
他賺了
5280 – 4000 = 1280
盈利百分率 = 1280x100% / 4000
= 32%

A.Money earned:

4000x1.2= 4800
the rest sold at 40%off of cost:
cost: 4000/5000 = $0.8/each orange
(5000-4000)x0.6x0.8= 480
Hence, the total money earned is 4800+480=$5280 YEAH!

B Profit percentage:

[(5280-4000)/4000]x100%= 32% That's it!

2006-11-14 23:58:38 補充：
but I have to remind you, the first solution on the top of the page is wrong, coz's his equation is wrong.

他共得:
$1.2×4000+($4000/5000)×60%×(5000-4000)

=$5280

盈利百分率是:
[(5280-4000)/4000]×100%

=32%