question: Find the average of the first 23 natural numbers?
Options:
(A) 8
(B) 9
(C) 10
(D) 11
(E) 12
answer: Stream of consciousness: Average of the first 'n' natural numbers = (n + 1)/2
We get (23 + 1)/2 = 12 The answer is (E).

q: If a man can cover 14 metres in one second, how many kilometres can he cover in 3 hours 45 minutes?
Options:
(A) 189km
(B) 195km
(C) 197km
(D) 200km
(E) 205km
a: Stream of consciousness: 14 m/s = 14 * 18/5 kmph
3 hours 45 minutes = 3 3/4 hours = 15/4 hours
Distance = speed * time = 14 * 18/5 * 15/4 km = 189 km. The answer is (A).

question: The speed of a boat in still water is 30kmph and the speed of the current is 20kmph. Find the speed downstream and upstream?
Options:
(A) kmph
(B) kmph
(C) kmph
(D) kmph
(E) kmph
answer: Stream of consciousness: Speed downstream = 30+ 20 = 50 kmph
Speed upstream = 30 - 20 = 10 kmph The answer is (B).

q: The average of first 15 even numbers is?
Options:
(A) 10
(B) 11
(C) 12
(D) 16
(E) 14
a: Stream of consciousness: Sum of 15 even numbers = 15 * 16 = 240
Average = 240/15 = 16 The answer is (D).

question: P and Q can complete a work in 20 days and 12 days respectively. P alone started the work and Q joined him after 4 days till the completion of the work. How long did the work last?
Options:
(A) 5 days
(B) 9 days
(C) 30 days
(D) 20 days
(E) 10 days
answer: Stream of consciousness: Work done by P in 1 day = 1/20
Work done by Q in 1 day = 1/12
Work done by P in 4 days = 4 (1/20) = 1/5
Remaining work = 1 1/5 = 4/5
Work done by P and Q in 1 day = 1/20 + 1/12 = 8/60 = 2/15
Number of days P and Q take to complete the remaining work = (4/5) / (2/15) = 6
Total days = 4 + 6 = 10 The answer is (E).

question: If rupee one produces rupees nine over a period of 54 years, find the rate of simple interest?
Options:
(A) 22 1/7 %
(B) 22 3/2 %
(C) 22 1/8 %
(D) 22 1/2 %
(E) 16 2/3 %
answer:
Stream of consciousness: 9 = (1*54*R)/100
R = 16 2/3 % The answer is (E).