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: 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).

question: The average of 10 numbers is calculated as 5. It is discovered later on that while calculating the average, one number namely 36 was wrongly read as 26. The correct average is?
Options:
(A) 2
(B) 3
(C) 4
(D) 5
(E) 6
answer: Stream of consciousness: 10 * 5 + 36 26 = 60/10 = 6 The answer is (E).

q: If a man can cover 16 metres in one second, how many kilometres can he cover in 3 hours 45 minutes?
Options:
(A) 118 km
(B) 162 km
(C) 216 km
(D) 1887 km
(E) 177 km
a: Stream of consciousness: 16 m/s = 16 * 18/5 kmph
3 hours 45 minutes = 3 3/4 hours = 15/4 hours
Distance = speed * time = 16 * 18/5 * 15/4 km = 216 km. The answer is (C).

question: The average age of a class of 42 students is 16 yrs. if the teacher's age is also included, the average increases by one year. Find the age of the teacher
Options:
(A) 30 Years
(B) 31 Years
(C) 32 Years
(D) 34 Years
(E) 59 Years
answer: Stream of consciousness: Total age of students is 42X16 = 672 Years
Total age inclusive of teacher = 43X (16+1) = 731
So, Teacher's age is 731-672 = 59 Yrs
There is a shortcut for these type of problems
Teacher's age is 16+(43X1) = 59 Years The answer is (E).

q: The speed of a boat in still water is 60kmph and the speed of the current is 20kmph. Find the speed downstream and upstream?
Options:
(A) 30/90 kmph
(B) 80,40 kmph
(C) 24,98 kmph
(D) 30,54 kmph
(E) 45.98 kmph
a: Stream of consciousness: Speed downstream = 60 + 20 = 80 kmph
Speed upstream = 60 - 20 = 40 kmph The answer is (B).

q: In how many different ways can the letters of the word 'PREPTY' be arranged?
Options:
(A) 120
(B) 230
(C) 330
(D) 340
(E) 360
a:
Stream of consciousness: Number of ways = 61/21 6X5X4X3X2X1 - 360 The answer is (E).