中一級數學新領域(英文版)問題

Ngyeesum

2011-12-29 3:13 am

18.Rebecca spent $12000 on buying the shares of a company at the beginning ofFebruary.(a) After a month,the value of the shares increased by 12%.What was the value of theshares at thebeginning of march?(b) At the beginning of Apri,the value of the shares was 30% less than that at the beginning of March.What was the value of the shares at the beginning of April? 19.If the numerator of 2/5 increases by 50% and its denominator decreases by 20%,find the new fraction. 20.The length and width of a rectangular lawn are 200 m and 150 m respectively. If the length and width decrease by 10% and 6% respectively.(a)Find the new area.(b)Find the percentage decrease in area. 21.The scores of team A and team B were the same at the beginning of a competition.After a round,the score of team A increased by 80,and that of team B increased to 240(a) if the score of team A increased by 40%,find the scores of the two teams at the beginning.(b) Find the percentage increase in the score of team B.

回答 (1)

βαβγ

2011-12-29 5:44 am

✔ 最佳答案

18(a)the value of the shares at the beginning of march
=12000x(1+12%)
=$14400
18(b)the value of the shares at the beginning of April
=14400x(1-30%)
=$10080

19)the new fraction
=2x(1+50%)/(5x(1-20%))
=3/4

20(a)the new area
=200x(1-10%)x150x(1-6%)
=25380m2
20(b) the percentage decrease in area
=(200x150-25380)/200x150x100%
=30000-25380/30000x100%
=15.4%

21(a)the scores of the two teams at the beginning
=80/(40%)
=200
21(b) the percentage increase in the score of team B
=240-200/200x100%
=20%

參考: 其實ed題目唔洗答句.

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