form 1 maths

Q1)Uncle bought 600 oranges for $500.Among them 25 are rotten,and the rest are sold at $2 each.Find the profit percent.

Total income
= (600-25) * $2
= $1150

Profit percentage
= ($1150 - $500) / $500 * 100%
= 650/500 * 100%
= 130%

So the profit percentage is 130%

2007-01-14 13:41:24 補充：
小小補充：計算 profit percentage 要先知道成本 (cost) 及收入 (income) 再用profit percentage = (income - cost) / cost * 100% 現在cost = $500income = (600-25) * $2 【600 個橙有 25 個爛的，其餘的每個 $2】

cost: $500
selling price: (600-25)*2=$1150
profit: 1150-500=$650
profit percent: 650/500*100%=130%
Therefore, the profit percent is 130%

The profit percent is:

$(600 - 25) x2 - $500
----------------------------- x 100%
　$500

　$575 x 2 - $500
= ---------------------- x 100%
　$500

　$1150 - $500
= -------------------- x 100%
　　$500

$650
= --------- x 100%
$500

= 130 %

∴ The profit percent is 130 %

[(600 - 25) x 2 - 500] / 500 x 100%
=130%