F.2 maths - Ans.fyi 參考答案

F.2 maths

chi ming

2008-02-29 6:41 am

1.For two consecutive multiples of 3,5times the larger number is not less than 2 times the smaller number plus 45. Find the minimum values of these two numbers.

2.A shopkeeper sells articles A and B. For each article A nd B sold, he can earn $50 and $70 respectively. If the shopkeeper has sold 30 articles, find the minimum number of article B sold when the profit made is at least $1900.

please write into detail.

回答 (1)

[匿名]

2008-02-29 6:55 am

✔ 最佳答案

1.
Let x be the smaller number, then the larger number is x 3

5(x 3) > = 2x 45
5x > = 2x 30
x > = 10

Therefore the minimum values of these two numbers are 12 and 15.

2.
Let x be the number of article B sold by the shopkeeper, then number of article A sold by the shopkeeper = 30 - x

50(30-x) 70x > = 1900
1500 20x > = 1900
20x > = 400
x > = 20

Therefore the minimum number of article B sold by the shopkeeper is 20

2008-02-28 22:55:31 補充：
> = 即是大過或等於

2008-02-28 22:56:35 補充：
1.
Let x be the smaller number, then the larger number is x + 3

5(x + 3) > = 2x + 45
5x > = 2x + 30
x > = 10

2008-02-28 22:57:25 補充：
2.
Let x be the number of article B sold by the shopkeeper, then number of article A sold by the shopkeeper = 30 - x

50(30-x) + 70x > = 1900
1500 + 20x > = 1900
20x > = 400
x > = 20

👍 0 👎 0