请教几道数学题

请教以下几道题的思路：谢谢

1. If the drama club and music club are combined, what percent of the combined membership will be male?

(1) Of the 16 members of the drama club,15 are male.

(2) Of the 20 members of the music club,10 are male.

[E]

2.                         T

                                                ● U

                             ●

                             S

The circle shown has center R.  If arc UST has length 48π, what is the radius of the circle?

A.      18

B.      24

C.      32

D.     48

E.      64

[C]

3.

A total of $60,000 was invested for one year.  Part of this amount earned simple annual interest at the rate of x percent per year, and the rest earned simple annual interest at the rate of y percent per year.  If the total interest earned by the $60,000 for that year was $4,080, what is the value of x?

(1)     x =

(2)   The ratio of the amount that earned interest at the rate of x percent per year to the amount that earned interest at the rate of y percent per year was 3 to 2.

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.

Answer:

[C]

4. In the decimal representation of x, where 0 < x < 1, is the tenths digit if x nonzero?

(1)     16x is an integer.

(2)     8x is an integer.

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.

Answer:

5. If x and y are positive integers such that 8y+12, what is the greatest common divisor of x and y?

(1) X=12u, where u is an integer

(2) Y=12z, where z is and integer

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.

Answer: