中一Maths 題！請高人列式！
A furniture manufacturer sold a chair and a table for $x and $2.5x repectively to a merchant. The merchant then sold the chair at a loss of 40% and the table at a profit of 40%. Did the merchant make an overall profit or loss , and by what per cent ? (已知答案 17.1/7%)
中一Maths 題！請高人列式！
2011-12-07 7:03 am
回答 (3)
2011-12-07 7:33 am
✔ 最佳答案
{[(100%-40%)x + (100%+40%)2.5x] - (x + 2.5x) } / (x + 2.5x)
= (0.6x + 3.5 x -3.5 x) / 3.5x
= 17.1/7 %
2011-12-07 9:29 pm
The loss of the chair is:x÷(1-40%)=5/3x
The profit of the table is:(2.5x)(1+40%)=7/2x
[(5/3x+7/2x)-(x+2.5x)÷(x+2.5x)]×100%
=(5/3x÷3.5x)×100%
=(10/21)×100%
=17.1/7%
The merchant made an overall profit is17.1/7%.
The profit of the table is:(2.5x)(1+40%)=7/2x
[(5/3x+7/2x)-(x+2.5x)÷(x+2.5x)]×100%
=(5/3x÷3.5x)×100%
=(10/21)×100%
=17.1/7%
The merchant made an overall profit is17.1/7%.
2011-12-07 8:20 am
not recommend to show one step to get the answer
recomment to show step by step, you, even the marker can double check it easier
2011-12-07 00:20:31 補充：
by merchant
total cost : X + 2.5X = 3.5X
chair : (1-40%)X = 0.6X
table : 2.5(1+40%)X = 3.5X
total received : 0.6X + 3.5X = 4.1X
% change = 100% x (4.1X - 3.5X) / 3.5X = 120/7 % (>0 means profits)
and you can developE a single step equation as below,
% change = 100% x (4.1X - 3.5X) / 3.5X
% change = 100% x [(0.6X+3.5X) - (X+2.5X)] / [X+2.5X]
% change = 100% x {[(1-40%)X + 2.5(1+40%)X] - [X+2.5X]} / [X+2.5X]
recomment to show step by step, you, even the marker can double check it easier
2011-12-07 00:20:31 補充：
by merchant
total cost : X + 2.5X = 3.5X
chair : (1-40%)X = 0.6X
table : 2.5(1+40%)X = 3.5X
total received : 0.6X + 3.5X = 4.1X
% change = 100% x (4.1X - 3.5X) / 3.5X = 120/7 % (>0 means profits)
and you can developE a single step equation as below,
% change = 100% x (4.1X - 3.5X) / 3.5X
% change = 100% x [(0.6X+3.5X) - (X+2.5X)] / [X+2.5X]
% change = 100% x {[(1-40%)X + 2.5(1+40%)X] - [X+2.5X]} / [X+2.5X]
收錄日期: 2021-04-26 22:21:47
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20111206000051KK01020