涛涛数学的解释，求解这几到题

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%

A collection of 36 cards consists of 4 sets of 9 cards each.  The 9 cards in each set are numbered 1 through 9.  If one card has been removed from the collection, what is the number on that card?

(1)     The units digit of the sum of the numbers on the remaining 35 cards is 6.

(2)     The sum of the numbers on the remaining 35 cards is 176.

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.

Q22:

A construction company was paid a total of $500,000 for a construction project.  The company’s only costs for the project were for labor and materials.  Was the company’s profit for the project greater than $150,000?

(1)     The company’s total cost was three times its cost for materials.

(2)     The company’s profit was greater than its cost for labor.

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.

Q23:

 AMOUNT OF BACTERIA PRESENT

Data for a certain biology experiment are given in the table above.  If the amount of bacteria present increased by the same fraction during each of the two 3-hour periods shown, how many grams of bacteria were present at 4:00 P.M.?

A.      12.0

B.       12.1

C.      12.2

D.      12.3

E.       12.4

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

Q26:

There are 8 books on a shelf, of which 2 are paperbacks and 6 are hardbacks.  How many possible selections of 4 books from this self include at least one paperback?

A.      40

B.       45

C.      50

D.      55

E.       60

Q31:

There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines.  If 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected?

A.      1/2

B.       2/3

C.      32/35

D.      11/12

E.       13/14

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%