Question: The edge of a cube is 5a cm. Find its surface?
Options:
(A) 24a8
(B) 150a2
(C) 24a1
(D) 24a2
(E) 24a7
Answer: 6a2 = 6 * 5a * 5a = 150a2
The answer is (B).

Question: You have a flashlight that takes 2 working batteries. You have 8 batteries but only 4 of them work.
What is the fewest number of pairs you need to test to guarantee you can get the flashlight on?
Options:
(A) 5
(B) 8
(C) 7
(D) 6
(E) 4
Answer: If you break the batteries into 3 groups: Two groups of 3 and one group of 2. By doing this you guarantee that one of the groups has 2 working batteries. Both of the groups of 3 have 3 possible combinations of 2 batteries and the group of 2 only has 1 combination. So, 3 + 3 + 1 = 7 tries at most to find two working batteries.
The answer is (C).

Question: The average age of a family of 6 members is 22 years.If the age of the youngest member is 7 years,what was the average age of the family at the birth of the youngest member?
Options:
(A) 15
(B) 18
(C) 21
(D) 12
(E) 19
Answer: Present age of total members = 6 X 22 = 132
7 yrs back their ages were = 6 x 7 = 42
Ages at the birth of youngest member = 132 - 42 = 90
Therefore, avg age at the birth of youngest member = 90/6 = 15.
The answer is (A).

Question: A 160 meter long train crosses a man standing on the platform in 16 sec. What is the speed of the train?
Options:
(A) 36 kmph
(B) 54 kmph
(C) 92 kmph
(D) 86 kmph
(E) 76 kmph
Answer:
S = 160/16 * 18/5 = 36 kmph
The answer is (A).