大家讨论一下GWD31套2中的几道数学题

Paulin

有四道题目请各位NN帮忙解答一下,非常感谢!!!

Q6:

 

20 ft

 

 

 

 

 

 

 

 

 

The figure above shows the dimensions of a semicircular cross section of a one-way tunnel.  The single traffic lane is 12 feet wide and is equidistant from the sides of the tunnel.  If vehicles must clear the top of the tunnel by at least ½ foot when they are inside the traffic lane, what should be the limit on the height of vehicles that are allowed to use the tunnel?

 

A.     5½ ft

B.     7½ ft

C.     8 ½ ft

D.     9½ ft

E.      10 ft

Answer: A     B

Q18:

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%

Answer: E (?)--------C

Q25:

A certain roller coaster has 3 cars, and a passenger is equally likely to ride in any 1 of the 3 cars each time that passenger rides the roller coaster.  If a certain passenger is to ride the roller coaster 3 times, what is the probability that the passenger will ride in each of the 3 cars?

 

A.     0

B.     1/9

C.     2/9

D.     1/3

E.      1

Answer: D--------C

Q33:

In Town X, 64 percent of the population are employed, and 48 percent of the population are employed males.  What percent of the employed people in Town X are females?

 

A.     16%

B.     25%

C.     32%

D.     40%

E.      52%

Answer: C--------------B不知道怎么算成这答案的，我计算是.64x.52x100%,约等于33%。

天天灿烂

去数学区看看吧。