標題:
math Q (help!)
發問:
Q1. Mary bought a dress with 25% discount. She paid $240 for it.(a) Find the original price of the dress. 這條是否這樣做: 240÷(1-25%)=$320(b) If the cost of the dress is $100, find the percentage after selling the dress to Mary. 這條是否這樣做:... 顯示更多 Q1. Mary bought a dress with 25% discount. She paid $240 for it. (a) Find the original price of the dress. 這條是否這樣做: 240÷(1-25%)=$320 (b) If the cost of the dress is $100, find the percentage after selling the dress to Mary. 這條是否這樣做: [(240-100)÷100]×100%=140% ------------------------------------------------------------------------------------------------------------------- Q2. A shop offers a 25% discount to a products A with marked price $800. The profit of selling the products is $120. (a) Find the cost of the products A. (b) If the selling proce of another products B is $700 which makes a profit of 75%, is the cost of B higher than A? Explain your answer. -------------------------------------------------------------------------------------------------------------------- Q3. 5 students finished a job in 6 days. For the same job, ｍ students finish the job in ｎ days. (Assume that the efficiency of each student is the same.) (a) Express ｍ in terms of ｎ. 這條是否這樣做: (5÷6) = (ｍ÷ｎ) ｎ = 6ｍ/5 (b) If 12 students work together, how many days do they need to finish the job? 這條是否這樣做: ｎ= (6×12)÷5=14.4 (15 days) ------------------------------------------------------------------------------------------------------------------- Q4. The standard deviation of the marks of S6 students in the mid-term Mathematics examination is 8 marks. After reviewing the marked papers by the teacher, he finds that there is a mistake of one question, thus 4 marks are added to all students. Also, it is given that the weight of the mid-term examination is 40%. (a) Find the weighted standard deviation of the marks after adjustment. (b) Will the standard score of each student be changed after adjustment? Explain your answer. -------------------------------------------------------------------------------------------------------------------- Thank you very much!
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Q.1 (a) The original price of the dress = $240 ÷ (1 - 25%) = $320 (b) The percentage profit = [(240 - 100)/100] x 100% = 140% Q.2 (a) Selling price of product A = $800 x (1 - 25%) = $600 Cost of product A = $(600 - 120) = $480 (b) Cost of product B = $700 ÷ (1 + 75%) = $400
其他解答:
Q1 岩左 Q2a 標價係800$ 比25% 折扣 公司可以有 120 利潤 即係: 先計 貨物折扣後的價錢 再因為利潤 = 標價 減 成本 最後可以得出 貨物的成本 2b 700$ 標價, 其中75% 係利潤~~ 所以剩返的 25% 就係 成本 比較返上面~ 可以知 3 4 一陣再睇....
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