q: If 80 percent of the test takers taking an old paper and pencil GMAT exam answered the first question on a given math section correctly, and 75 percent of the test takers answered the second question correctly, and 5 percent of the test takers answered neither question correctly, what percent answered both correctly?
Options:
(A) 60 %
(B) 65 %
(C) 70%
(D) 75%
(E) 80%
a: Stream of consciousness: {Total} = {First correctly} + {Second correctly} - {Both correctly} + {Neither correctly}
100 = 80 + 75 - {Both correctly} + 5
{Both correctly} = 60. The answer is (A).

question: 80 370 860 1550 2440 ?
Options:
(A) 900
(B) 840
(C) 750
(D) 860
(E) 3530
answer: Stream of consciousness: 10^2 - 20 = 80
20^2 - 30 = 370
30^2 - 40 = 860
40^2 - 50 = 1550
50^2 - 60 = 2440
60^2 - 70 = 3530. The answer is (E).

q: In Badminton game, one player throws two fair, six-sided die at the same time. If the player receives at least a five or a one on either die, that player wins. What is the probability that a player wins after playing the game once?
Options:
(A) 1/3
(B) 4/9
(C) 5/9
(D) 2/3
(E) 3/4
a: Stream of consciousness: In Badminton game, Probably the easiest approach would be to find the probability of the opposite event and subtract it from 1:
P(win) = 1- P(not win) = 1 - 4/6*4/6 = 5/9. The answer is (C).

question: What is the Mode of the following data set S- {1,2,6,9,6,6,10}
Options:
(A) 9
(B) 6
(C) 10
(D) 1
(E) 2
answer: Stream of consciousness: Mode of a set is the data point that is repeated the most number of times. In the set given, 6 is repeated. The answer is (B).

q: A train 540 meters long is running with a speed of 54 kmph. The time taken by it to cross a tunnel 180 meters long is?
Options:
(A) 66 sec
(B) 46 sec
(C) 48 sec
(D) 65 sec
(E) 64 sec
a: Stream of consciousness: D = 540 + 180 = 720
S = 54 * 5/18 = 15 mps
T = 720/15 = 48 se The answer is (C).

q: There are 25 balls in a jar. You take out 5 blue balls without putting them back inside, and now the probability of pulling out a blue ball is 1/5. How many blue balls were there in the beginning?
Options:
(A) 12.
(B) 9.
(C) 8.
(D) 7.
(E) 6.
a:
Stream of consciousness: 9 = 5 blue balls + 20/ 5 The answer is (B).