question: 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 400 newborn members of the population, approximately how many would be expected to survive the first 3 months of life?
Options:
(A) 240
(B) 246
(C) 252
(D) 292
(E) 298
answer: Stream of consciousness: Number of newborns that can die in first month = 1/10 * 400 = 40
Survived = 360
Number of newborns that can die in second month = 1/10 * 360 = 36
Survived = 324
Number of newborns that can die in third month = 1/10 * 324 = 32
Survived = 292 The answer is (D).

q: On 3,000 invested at a simple interest rate 6 p.c.p.a, 900 is obtained as interest in certain years. In order to earn 1,600 as interest on 4,000 in the same number of years, what should be the rate of simple interest?
Options:
(A) 7 p.c.p.a.
(B) 8 p.c.p.a.
(C) 9 p.c.p.a.
(D) Data inadequate
(E) None of these
a: Stream of consciousness: Time = 900100/30006 = 5 years
Rate = 1600100/54000 = 8% The answer is (B).

question: There are 8 books in a shelf that consist of 1 paperback books and 7 hardback books. If 4 books are selected at random without replacement, how many different combinations are there that at least one paperback book is selected?
Options:
(A) 35
(B) 45
(C) 50
(D) 55
(E) 60
answer: Stream of consciousness: 8C4 [Select any four] - 7C4 [Select all hard backs] = 35. The answer is (A).

q: A train 500 meters long completely crosses a 300 meters long bridge in 45 seconds. What is the speed of the train is?
Options:
(A) 32
(B) 28
(C) 49
(D) 64
(E) 21
a: Stream of consciousness: S = (500 + 300)/45 = 800/45 * 18/5 = 64 The answer is (D).

question: Mice can multiply very fast. Adult mice can give birth once every month, and baby mice grow into adult mice in just two months after they are born. If you would buy a baby mouse just after it was born, how many mice would you have in 10 months?
Options:
(A) 1
(B) 2
(C) 3
(D) 4
(E) 5
answer: Stream of consciousness: One. You cannot have more mice if you start with one! The answer is (A).

question: How much is 80% of 40 is greater than 4/5 of 25?
Options:
(A) 29
(B) 776
(C) 66
(D) 12
(E) 99
answer:
Stream of consciousness: (80/100) * 40 (4/5) * 25
32 - 20 = 12 The answer is (D).