求助

Lionback

这题我怎么不明白呢？哪位好心人指点一下？？

On a certain transatlantic crossing, 20 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship.  If 60 percent of the passengers with round-trip tickets did not take their cars abroad the ship, what percent of the ship’s passengers held round-trip tickets?

 

A.     33 1/3%

B.     40%

C.     50%

D.     60%

E.      66 2/3%

Lionback

谁能指点一下呀

Lionback

还有一题不明白，希望哪位高人可以点拔一下！！！

 

Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m.  By what percent did the ratio of price per share to earnings per share increase, in terms of k and m?

 

A.     k/m%

B.     (k – m) %

C.     [100(k – m)] / (100 + k) %

D.     [100(k – m)] / (100 + m) %

E.      [100(k – m)] / (100 + k + m) %

puzzlei

C、D ?

michael_mei

Answer to 3rd floor:

question is about the increased ratio of Price/Earning(P/E).

previous year: P/E

this year: P(1+k%)/E(1+m%),

So the increased ratio is [P(1+k%)/E(1+m%)-P/E]/[P/E]=(1+k%)/(1+m%)-1=(k-m)/(100+m)= [100(k-m)]/(100+m) %, So D is correct.

kelly41099

Answer:

R ---- Passengers with round-trip tickes

P----- All passengers

(1-60%)*R -----passenger with round-trip tickes and took cars

(1-60%)*R=20%*P   --àR/P=50%

Lionback

谢谢，万分感谢，高人真是不同呀，小弟在此谢过