q: In a class, the average age of 45 boys is 10 years and the average of 15 girls is 10 years. what is the average age of the whole class?
Options:
(A) 12 Years
(B) 12.3 Years
(C) 10 Years
(D) 13 Years
(E) 15 Years
a: Stream of consciousness: Total age of 60 students
(45X 10+15 X 10) = 630
Average = 600/60 = 10 Years The answer is (C).


question: At 15:00 there were 20 students in the computer lab. At 15:03 and every three minutes after that, 4 students entered the lab. If at 15:10 and every ten minutes after that 8 students left the lab, how many students were in the computer lab at 15:44 ?
Options:
(A) 7
(B) 14
(C) 25
(D) 27
(E) 30
answer: Stream of consciousness: Initial no of students + 3 * (1 + No of possible 3 minute intervals between 15:03 and 15:44) -
8 *(1 + No of possible 10 minute intervals between 15:10 and 15:44)
20 + 3*14 -8 * 4 = 27 The answer is (D).


q: 30 pens and 75 pencils were purchased for 450. If the average price of a pencil was 2.00, find the average price of a pen.
Options:
(A) 10
(B) 11
(C) 12
(D) 13
(E) 14
a: Stream of consciousness: Since average price of a pencil = 2
∴ Price of 75 pencils = 150
∴ Price of 30 pens = (450 – 150) = 300
∴ Average price of a pen = 360⁄60 = 10 The answer is (A).


question: Marry has 3 trousers in cupboard. One of them is grey the 2nd blue and the 3rd brown. In his wardrobe he also has 4 shirts. One of them is grey and the other 3are white. He opens his cupboardin the dark and pick out one shirt trouser pair without examination the color. What is the likelihood that neither the shirt nor the trouser is grey?
Options:
(A) 1/2
(B) 2/3
(C) 3/5
(D) 5/7
(E) 5/8
answer: Stream of consciousness: Probability that trouser is not grey = 2/3
Probability that shirt is not grey = 3/4
∴ Required probability = 2/3 x 3/4 = 1/2 The answer is (A).


q: Pipes A and B can fill a cistern in 8 and 24 minutes respectively. They are opened an alternate minutes. Find how many minutes, the cistern shall be full?
Options:
(A) 11
(B) 12
(C) 99
(D) 75
(E) 72
a: Stream of consciousness: 1/8 + 1/24 = 1/6
6 * 2 = 12 The answer is (B).


q: Two persons A and B can complete a piece of work in 30 days and 45 days respectively. If they work together, what part of the work will be completed in 7 days?
Options:
(A) 2/5
(B) 7/18
(C) 1/4
(D) 1/9
(E) 2/6
a:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Stream of consciousness: A's one day's work = 1/30
B's one day's work = 1/45
(A + B)'s one day's work = 1/30 + 1/45 = 1/18
The part of the work completed in 7 days = 7 (1/18) = 7/18. The answer is (B).