唔識做E條數

[(500x90%)x1.8]-400 除 400 乘100%
= 102.5%
the profit percent is 2.5%

唔知arm 5 arm架!?

The profit percentage:
(1.8 x 500 x 0.9)-400 / 400 x 100%
= 1.025 x 100%
=102.5%

The profit percentage is 102.5%

其實到你真係做果時括號未必需要,但可以方便你看清楚
500x0.9 係 無壞可以賣的
而the total amout of money gain from it= 1.8 x 500 x 0.9
之後使用percentage之算式:
new-old/ old x 100%
就ok ga la~
如果你一條formula 做唔晒的話
試試^^分開幾條式思考~就可以好一點點

weight of potatioes that are good = 500kg x (1-0.1) = 450kg

the amount the grocer earned = 450kg x $1.8/kg = $810

the profit percent = [($810-$400) / $400] x 100% = 102.5%

2007-11-16 21:54:08 補充：
samantha_cheng0116 計錯數啦 (我只是發表意見, 唔係寸佢)profit percent 是102.5%, 唔係2.5%另外, 事先聱明, 我唔係抄thanks_258的答案ga 最後, 提提你以上英文 (因為了解題目對答題目有幫助):rotten: 腐爛的 ==> 所以唔係腐爛, 就是好的啦amount earned: 賺到的錢profit: 利潤 [是把賺到的錢 ($810), 減去成本 ($410)]希望... 對你有幫助 ^_^

Weight of potatoes that are good = 500*(1-10%) = 500*0.9 = 450 kg
Total profit = 450*1.8 - 400 = 410
Profit percentage = 410/400 * 100% = 102.5%