percentage change既mathz` 吾該幫幫忙

2008-10-10 4:33 am

i need the steps!Thz for all your help!=]

1)Goods are marked at a price which gives a trader a profit of 28%.What percentage discount on the marked price has he allowed if he actually gains 12%?

2)At what price must a shopkeeper mark an article costing $180 so that he can allow a discount of 10% on the marked price and still make a profit of 10% on the cost price?

3)A is 25% taller than B and B is 25% shorter than C.What is the ratio of A's height to C's height?

回答 (1)

Jonathan

2008-10-10 7:18 am

✔ 最佳答案

Q.1
Let C be the cost, P be the Price and x be the percentage discount:
C ( 1 28%) = P
1.28 C = P -----------------------------(1)

C ( 1 12% ) = P (1-x% )
1.12 C = P (1-x%) ---------------------(2)

Put (1) into (2),

1.12 C = 1.28 C (1-x%)
(1.12 C) / (1.28 C) = 1-x%
0.875 = 1 - x%
x / 100 = 1 - 0.875
x / 100 = 0.125
x = 12.5

Q.2
Let P be the selling price,
P ( 1-10%) = C ( 1 10%)
0.9 P = 1.1 C

As C=180, then we have:
0.9 P = 1.1 x 180
P = 220

Q.3
A = 1.25 B ---------(1)
B = 0.75 C ---------(2)

Put (2) into (1),
A = 1.25 x 0.75 C
A/C = 0.9375 ( i.e. A is 6.25% shorter than C)

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