q: The average of seven numbers is 18. The average of first three numbers is 12 and the average of last three numbers is 19. What is the middle number?
Options:
(A) 25
(B) 27
(C) 29
(D) 33
(E) 34
a: Stream of consciousness: The total of seven numbers = 7X18 = 126
The total of first 3 and last 3 numbers is = 3 X 12+3 X 19 = 99
So, the middle number is (126 - 93 ) = 33 The answer is (D).

question: A train 250 m long, running with a speed of 50 km/hr will pass a tree in?
Options:
(A) 18sec
(B) 20sec
(C) 25sec
(D) 30sec
(E) 1min
answer: Stream of consciousness: Speed = 50 * 5/18 = 125/9 m/sec
Time taken = 250 *9/125 = 18 sec The answer is (A).

q: How many digits are in the number 50^8 8^3 11^3?
Options:
(A) 22
(B) 20
(C) 19
(D) 18
(E) 17
a: Stream of consciousness: Whenever you are asked to find the number of digits, try to bring the number in multiples of 10. This way, we can wasily calculate the umber of 0's through the powers of 10
50^8 8^3 11^3 = (5^2*2)^8*2^9*11^3 = 5^16*2^17*11^3 = 2*11^3*10^16 = 2662*10^16
Hence we would have 16 trailing 0's and the three digits from 2662
Total digits = 4 + 16 = 20 The answer is (B).

question: The distance between West-Town to East-Town is 15 kilometers. Two birds start flying simultaneously towards one another, the first leaving from West-Town at a speed of 2 kilometers per minute and the second bird, leaving from East-Town, at a speed of 1 kilometers per minute. What will be the distance, in kilometers, between the meeting point and West-Town?
Options:
(A) 3.
(B) 7.
(C) 10.
(D) 12.
(E) 15.
answer: Stream of consciousness: Time taken by the birds to meet = 15/(2 + 1) = 5 mins
Distance traveled by the bird traveling from West-Town = 2 * 5 = 10 The answer is (C).

q: The speed of a boat in upstream is 100 kmph and the speed of the boat downstream is 130 kmph. Find the speed of the boat in still water and the speed of the stream?
Options:
(A) 170, 10 kmph
(B) 35, 27 kmph
(C) 50, 60 kmph
(D) 115, 15 kmph
(E) 45, 65 kmph
a: Stream of consciousness: Speed of the boat in still water = (100+130)/2 = 115 kmph. Speed of the stream = (100-130)/2 = 15 kmph The answer is (D).

q: Rs.800 amounts to Rs.920 in 3 years at simple interest. If the interest is increased by 3%, it would amount to how much?
Options:
(A) 226
(B) Rs.992
(C) 665
(D) 771
(E) 211
a:
Stream of consciousness: (800*3*3)/ 100 = 72
920 + 72 = 992 The answer is (B).