Rationale: Denote X as the sum of the heights of the two new people. From the stem it follows that (700+X)6>175. This reduces to X>350. Only the heights from B add up to 350 cm. All other pairs add up to more than 350 cm.
The answer: (B)
Question: The average height in a group of 4 people is 175 cm. If the average height increased when 2 more people were added to the group, which of the following cannot be the heights of the two new people?
Options:
(A) 179 cm and 172 cm
(B) 181 cm and 169 cm
(C) 173 cm and 178 cm
(D) 176 cm and 176 cm
(E) 174 cm and 177 cm
Reasoning: Part filled by (A + B + C) in 3 minutes = 3(1/30 + 1/20 + 1/10) = 11/20
Part filled by B in 3 minutes = 3/20
Required ratio = 3/20 * 20/11 = 3/11
Ans: (C)
Question: Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution Q in the liquid in the tank after 3 minutes?
Options:
(A) 1/11
(B) 2/11
(C) 3/11
(D) 4/11
(E) 5/11
Rationale: Use elimination method to find the correct option. you find that of all the options when 4 is the correct value for n
The answer: (E)
Question: Calculate the value of n from the below equation: n^310n+20=44
Options:
(A) 1
(B) 5
(C) 3
(D) 2
(E) 4
Reasoning: This alternating addition series begins with 3; then 1 is added to give 4; then 3 is added to give 7; then 1 is added, and so on.
Ans: (A)
Question: Look at this series: 3, 4, 7, 8, 11, 12, ... What number should come next?
Options:
(A) 15
(B) 14
(C) 17
(D) 12
(E) 19
Rationale: Answer: A. There is exactly one. The prime factorization of 14 is 14 = 2*7, so N = 2*7*p = 7*2*p = 7*2p, so 2p is the only even number that divides N.
The answer: (A)
Question: Let p be a prime number greater than 2 and let N = 14p. How many even numbers divide N?
Options:
(A) 1
(B) 2
(C) 3
(D) 4
(E) 5
Rationale: (60/100) * 50 (40/100) * 30
30 - 12 = 18
The answer: (A)
Question: How much 60% of 50 is greater than 40% of 30?
Options:
(A) 18
(B) 28
(C) 29
(D) 11
(E) 12