인터넷에서 구한 문제인데 답만 나와있어서 답답하네요. 아무리 제 머리로는 이해가 안 되는 문제 들입니다.
고수님들의 풀이 부탁드려요 감사합니다.
Q13:
If x and y are positive, is 3x > 7y?
(1) x > y + 4
(2) -5x < -14y
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: B
Q19:
A total of $60,000 was invested for one year. But 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 = (3/4) y
(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
Q26:
Running at their respective constant rates, machine X takes
2 days longer to produce w widgets than machine Y. At these rates, if the two machines together
produce 5/4 w widgets in 3 days, how many days would it take machine X alone to
produce 2w widgets?
A.
4
B.
6
C.
8
D.
10
E.
12
Answer: E
Q30:
Joanna bought only $0.15 stamps and $0.29 stamps. How many $0.15 stamps did she buy?
(1) She bought $4.40 worth of
stamps.
(2) She bought an equal number
of $0.15 stamps and $0.29 stamps.
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: D
Q31:
A positive integer n is said to be “prime-saturated” if the
product of all the different positive prime factors of n is less than the
square root of n. What is the greatest
two-digit prime-saturated integer?
A.
99
B.
98
C.
97
D.
96
E. 95
Answer: D