q: The average of first four prime numbers greater than 50 is?
Options:
(A) 50
(B) 57
(C) 89
(D) 56
(E) 60
a: Stream of consciousness: 53 + 59 + 61 + 67 = 240/4 = 60 The answer is (E).

question: How many two-digit numbers satisfy this property.: The last digit (unit's digit) of the square of the two-digit number is 8 ?
Options:
(A) 1
(B) 2
(C) 3
(D) 4
(E) none of these
answer: Stream of consciousness: A number ending in 8 can never be a perfect squar The answer is (E).

q: Find the average of the first 25 natural numbers?
Options:
(A) 8
(B) 9
(C) 13
(D) 11
(E) 12
a: Stream of consciousness: Average of the first 'n' natural numbers = (n + 1)/2
We get (25 + 1)/2 = 13 The answer is (C).

question: 30 pens and 75 pencils were purchased for 510. 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
answer: Stream of consciousness: Since average price of a pencil = 2
Price of 75 pencils = 150
Price of 30 pens = (510 150) = 360
Average price of a pen = 36060 = 12 The answer is (C).

q: A train 100 meters long completely crosses a 300 meters long bridge in 45 seconds. What is the speed of the train is?
Options:
(A) 25 kmph
(B) 32 kmph
(C) 40 kmph
(D) 38 kmph
(E) 92 kmph
a: Stream of consciousness: S = (100 + 300)/45 = 400/45 * 18/5 = 32 kmph The answer is (B).

q: The no. of girls in a class are 7times the no. of boys, which value cannever be the of total students?
Options:
(A) 20
(B) 35
(C) 30
(D) 40
(E) 42
a:
Stream of consciousness: Let the boys are X, then girls are 7X, total = X+7X = 8X
So it should be multiple of 8, 30 is not a multiple of 8. The answer is (C).