數學高手幫幫我-口-!

2008-10-28 4:50 am

1.A bicycle os $80 cheaper if it is sold at a discount of 20%.
a) What is the marked price of the bicycle?
b) If its selling price is %300, what si the discount per cent?

2. The original marked price of a watch is $700. The shop owner raises the marked price by 20% and then se;;s it at a discount of 15%. Find the selling price of the watch.

3. The members of a certain watch shop enjoy a discount of 15%. Miss Lee is a member of the watch shop and she has a $50 cash coupon of this shop. The coupon cannot be used with the other discount together. Now, Miss Lee wants to buy one of the following two watches, watch A($320) and watch B($360). State the watch she buys and whether she uses the coupon or not if she wants to buy the watch with
a) a higher discount,
b) a higher discount per cent.

更新1:

1.A bicycle is $80 cheaper if it is sold at a discount of 20%. a) What is the marked price of the bicycle? b) If its selling price is $300, what is the discount per cent?

更新2:

2. The original marked price of a watch is $700. The shop owner raises the marked price by 20% and then sells it at a discount of 15%. Find the selling price of the watch.

回答 (1)

Jessica

2008-10-28 5:31 am

✔ 最佳答案

1a)
Let $a be the marked price of the bicycle.
a*20% = 80
a= 400
Therefore, the marked price of the bicycle is $400.
b)
The discount per cent:
400-300/400 x 100%
= 25%
Therefore, the discount percent is 25%.

2)
The selling price of the watch:
700 x (1+20%) x (1-15%)
= 840 x (1-15%)
= $714

3a)
Money paid for watch A(coupon):
320-50
=$270
Money paid for watch A(member discount):
320 x (1-15%)
=$272
Money paid for watch B(coupon):
360-50
=$310
Money paid for watch B(member discount):
360 x (1-15%)
=$306

Because Wtatch B: 360-306 = $54,
which has the biggest discount among those method,
Miss Lee should buy watch B with member disount to get a higher discount.

Because the discount of watch A with coupon:
(320-270)/320 x 100%
= 15.625%
is the biggest discount percent among those method,
therefore Miss Lee should buy watch A with coupon to get a higher discount per cent.

參考: me:)

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