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? | 
