q: A and B can do a work in 18 days, B and C in 30 days and C and A in 36 days. In how many days will the work be completed, if all three of them work together?
Options:
(A) 360/13 days
(B) 350/13 days
(C) 160/13 days
(D) 260/13 days
(E) 960/13 days
a: Stream of consciousness: One day work of A and B = 1/18
One day work of B and C = 1/30
One day work of C and A = 1/36
2(A + B + C) = 1/18 + 1/30 + 1/36
2(A + B + C) = 21/180
(A + B + C) = 13/360
Number of days required = 360/13 days. The answer is (A).

question: 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) 29
(B) 18
(C) 48
(D) 99
(E) 11
answer: Stream of consciousness: D = 540 + 180 = 720
S = 54 * 5/18 = 15 mps
T = 720/15 = 48 se The answer is (C).

q: The edge of a cube is 3a cm. Find its surface?
Options:
(A) 64a2 cm2
(B) 54a2 cm2
(C) 84a2 cm2
(D) 24a2 cm2
(E) 34a2 cm2
a: Stream of consciousness: 6a2 = 6 * 3a * 3a = 54a2 The answer is (B).

question: Anitha had 80 currency notes in all, some of which are of Rs 95 denomination and the remaining of Rs 45 denomination. The total amount of all these currency notes was Rs. 4000. How much amount (in Rs) did she have in the denomination of Rs 45?
Options:
(A) 3500
(B) 72
(C) 2000
(D) 3000
(E) 4000
answer: Stream of consciousness: Let the number of 45-rupee notes = x
Then, the number of 95-rupee notes = (80 x)
45x + 95(80 x) = 4000 or x + 2(80 x) = 95 or x = 72. The answer is (B).

q: Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution R in the liquid in the tank after 3 minutes?
Options:
(A) 6/15
(B) 6/11
(C) 6/14
(D) 6/12
(E) 6/13
a: Stream of consciousness: Part filled by (A + B + C) in 3 minutes = 3(1/30 + 1/20 + 1/10) = 11/20
Part filled by C in 3 minutes = 3/10
Required ratio = 3/10 * 20/11 = 6/11 The answer is (B).

q: Find the mean proportional between 64 & 81?
Options:
(A) A) 59
(B) B) 61
(C) C) 63
(D) D) 72
(E) E) 67
a:
Stream of consciousness: Formula = ab
A = 64 and B = 81
6481 = 8 9 = 72 The answer is (D).