请教几道数学题，感谢解答

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.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

答案选C，本人选A：12x+8y=5040，x与y均为整数，难道得不出唯一答案么？

Last Sunday a certain store sold copies of Newspaper A for $1.00 each and copies of Newspaper B for $1.25 each, and the store sold no other newspapers that day.  If r percent of the store’s revenues from newspaper sales was from Newspaper A and if p percent of the newspapers that the store sold were copies of newspaper B, which of the following expresses r in terms of p?

A.    100p / (125 – p)

B.     150p / (250 – p)

C.     300p / (375 – p)

D.    400p / (500 – p)

E.     500p / (625 – p)

答案为D

涛涛数学30，你是怎么算的。第一题有人有思路么？下午就考了

急问急问，谢谢谢谢。