PS 問題

treewing929

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)

請問這條如何得到答案 D?? 感謝了!!

treewing929

The average (arithmetic mean) of the 5 positive integers k, m, r, s, and t is 16, and k < m < r < s < t.If t is 40, what is the greatest possible value of the median of the 5 integers?



A.16

B.18

C.19

D.20

E.22
答案是 B. 但有點不明白.
positive integers 不可以是 0 嗎?
0,1,19,20,40???
為何是 1,2,18,19,40?
謝謝大家!