q: In a certain animal population, for each of the first 3 months of life, the probability that an animal will die during that month is 1/10. For a group of 300 newborn members of the population, approximately how many would be expected to survive the first 3 months of life?
Options:
(A) 219
(B) 246
(C) 252
(D) 262
(E) 270
a: Stream of consciousness: Number of newborns that can die in first month = 1/10 * 300 = 30
Survived = 270
Number of newborns that can die in second month = 1/10 * 270 = 27
Survived = 243
Number of newborns that can die in third month = 1/10 * 243 = 24
Survived = 219 The answer is (A).

question: 189. The inside dimensions of a rectangular wooden box
are 8 inches by 10 inches by 12 inches. A cylindrical
canister is to be placed inside the box so that it stands
upright when the closed box rests on one of its six
faces. Of all such canisters that could be used, what is
the radius, in inches, of the one that has maximum
volume?
Options:
(A) 3
(B) 4
(C) 5
(D) 6
(E) 8
answer: Stream of consciousness: Since the radius is squared, the biggest volume cylinder will have the biggest possible radius. To achieve that, let the smaller dimension of the rectangular box be the height. So, it will have 12x10 width x length. The biggest cylinder must fit both dimensions, so it must have at most a diameter of 10, so the radius will be 5. The answer is (C).

q: If 4 women can color 48 m long cloth in 2 days, then 6 women can color 36 m long cloth in
Options:
(A) 2 days
(B) 3 days
(C) 1 day
(D) 4 days
(E) 5 days
a: Stream of consciousness: The length of cloth painted by one woman in one day = 48 / 4 2 = 6 m
No. of days required to paint 36 m cloth by 6 women = 36/ 6 6 = 1 day. The answer is (C).

question: 5,9,19,31,51,__
Options:
(A) 84
(B) 80
(C) 81
(D) 82
(E) 83
answer: Stream of consciousness: (9+5) +5 = 19
(16+9) +6 = 31
(28+16)+7 = 51
(48+28)+8 = 84 The answer is (A).

q: A bag contains 3 red and 2 black ball. Another bag contains 4 red and 5 black balls. A ball is drawn from the first bag and is placed in the second. A ball is then drawn from the second. What is the probability that this draw of red ball is due to the drawing of red ball from the first bag ?
Options:
(A) 3/5
(B) 2/5
(C) 4/25
(D) 3/10
(E) 15/23
a: Stream of consciousness: Probability of getting red ball from bag1 and then red from bag 2 = 3/5*5/10 = 15/50
Probability of getting black ball from bag1 and then red from bag 2 = 2/5*4/10 = 8/50
Now comes the condition, hence apply conditional probability:
P(Red)/ P(Red + Black)
(15/50)/(15/50+8/50) = 15/50 /23/50 = 15/23. The answer is (E).

q: A person spends 40% of his salary on food, 25% on house rent, 15% on entertainment and 15% on conveyance. If his savings at the end of the month is Rs. 1200, then his salary per month in rupees is:
Options:
(A) 4000
(B) 24000
(C) 8000
(D) 10000
(E) None of these
a:
Stream of consciousness: Total expenditure = 40 + 25 + 15 + 15 = 95%
Saving = (100 - 95) = 5%
5/100 Salary = 1200, Salary = 24000 Rs. The answer is (B).