GWD-6-12, GWD-6-30 两题类似，容易错。

hlin4 · 发表于 2005-9-14 03:11:00

Q12:

For a certain play performance, adults’ tickets were sold for $12 each and children’s tickets were sold for $8 each. How many children’s tickets were sold for the performance?

(1) The total revenue from the sale of adults’ and children’s tickets for the performance was $5,040.

(2) The number of adults’ tickets sold for the performance was 1/3 the total number of adults’ and children’s tickets sold for the performance.

answer: C

Q30:

Joanna bought only $0.15 stamps and $0.29 stamps. How many $0.15 stamps did she buy?

(1) She bought $4.40 worth of stamps.

(2) She bought an equal number of $0.15 stamps and $0.29 stamps.

answer: A

12. 设 adult 卖出m张， children卖出n张，所以， 12m + 8n = 5040; m, n 必为正整数, m可以有多个选择。

30. 同理， 15m + 29n = 440, 因为m, n 必为正整数， m这儿只能为10. (有什么快速方法计算吗?)

这两题极其类似，有什么好方法可以很快的算出"凑整数"吗?

Youknowme · 发表于 2005-9-14 12:31:00

以下是引用hlin4在2005-9-14 3:11:00的发言：

Q12:

For a certain play performance, adults’ tickets were sold for $12 each and children’s tickets were sold for $8 each. How many children’s tickets were sold for the performance?

(1) The total revenue from the sale of adults’ and children’s tickets for the performance was $5,040.

(2) The number of adults’ tickets sold for the performance was 1/3 the total number of adults’ and children’s tickets sold for the performance.

answer: C

这个题直接列方程组,设adult 卖出m张,children卖出n张,

12m+8n=5040

3m=m+n

然后解方程组

Q30:

Joanna bought only $0.15 stamps and $0.29 stamps. How many $0.15 stamps did she buy?

(1) She bought $4.40 worth of stamps.

(2) She bought an equal number of $0.15 stamps and $0.29 stamps.

answer: A

15m + 29n = 440, 因为m, n 必为正整数， m这儿只能为10

这题个人认为最好的方法就是代入法了

catcenter · 发表于 2006-5-18 15:54:00

我也这么觉得...这两题真混啊,不知道有什么好方法可以区别

catcenter · 发表于 2006-5-18 15:57:00

我只想到可能12题,8和12有相同的因子,所以较可能有多解

30题29是个PRIME,较不可能回有多解

...

还是请NN来看看

jingle0915 · 发表于 2010-8-13 19:59:05

还是请NN来看看

GWD-6-12, GWD-6-30 两题类似，容易错。