q: What amount does Kiran get if he invests Rs. 18000 at 15% p.a. simple interest for four years?
Options:
(A) 3888
(B) 26989
(C) 26700
(D) 28800
(E) 2879
a: Stream of consciousness: Simple interest = (18000 * 4 * 15)/100 = Rs. 10800
Amount = P + I = 18000 + 10800 = Rs. 28800 The answer is (D).

question: The H.C.F. of two numbers is 12 and their L.C.M. is 600. If one of the numbers is 720, then the other is:
Options:
(A) 8
(B) 10
(C) 12
(D) 4
(E) 6
answer: Stream of consciousness: Other number = (12 x 600)/720 = 10. The answer is (C).

q: For some integer p, p^2 - 5 is divisible by all of the following EXCEPT
Options:
(A) 30
(B) 38
(C) 41
(D) 29
(E) 31
a: Stream of consciousness: Hint: p^2-5 (p is an integer) is never multiple of 3 (try to prove this), hence 30 is out. The answer is (A).

question: What is the area of a square with perimeter 12P ?
Options:
(A) 16p^2
(B) 4P
(C) 9P^2
(D) P/16
(E) P^2/16
answer: Stream of consciousness: Each side is 3p
A = (3p)^2 = 9p^2 The answer is (C).

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 farm used two harvesting machines, H and K, to harvest 100 acres of wheat. Harvesting machine H, working alone at its constant rate, harvested 40 acres of wheat in 8 hours. Then harvesting machine K was brought in, and harvesting machines H and K, working together at their respective constant rates, harvested the remaining acres of wheat in 4 hours. Harvesting machine K harvested how many acres of wheat per hour?
Options:
(A) 7
(B) 8
(C) 11
(D) 13
(E) 15
a:
Stream of consciousness: Rate of H = 4 acres/hr
Remaining land to be harvested = 100 - 40 = 60
Rate of H and K = 60/4 = 15 acres/hr
Rate of K = 15- 4 = 11 The answer is (C).