Q: What is the least number should be added to 1056, so the sum of the number is completely divisible by 28?
Options:
(A) 1
(B) 2
(C) 3
(D) 4
(E) 8
A: OK... Stream of consciousness: (1056 / 28) gives remainder 20
20 + 8 = 28, So we need to add 8
The answer is (E).

Q: During a particular baseball game, the probability of a team's pitcher throwing a strike on each throw is 2/5. What is the least number of times that the pitcher should pitch the ball that will increase the probability of getting a strike at least once to more than 50%.
Options:
(A) 3
(B) 2
(C) 1
(D) 4
(E) 5
A: OK... Stream of consciousness: Rule of Subtraction: P(A) = 1 - P(A')
Rule of Multiplication: P(A B) = P(A) P(B)
The probability that the pitcher throws a strike at least once in 2 guesses is 1- (3/5)^2 = 1 - 9/25 = 16/25 > 50%.
The answer is (B).

Q: The average of 15 result is 60. Average of the first 10 of them is 10 and that of the last 10 is 80. Find the 8th result?
Options:
(A) 35
(B) 200
(C) 150
(D) 250
(E) 300
A: OK... Stream of consciousness: Sum of all the 13 results = 15 * 60 = 900
Sum of the first 7 of them = 10 * 10 = 100
Sum of the last 7 of them = 10 * 80 = 800
So, the 8th number = 900 + 100 - 800 = 200.
The answer is (B).

Q: A man rows his boat 85 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?
Options:
(A) 7 kmph
(B) 6 kmph
(C) 5 kmph
(D) 8 kmph
(E) 2 kmph
A:
OK... Stream of consciousness: Speed downstream = d/t = 85/(2 1/2) = 34 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (34 - 18)/2 = 8 kmph
The answer is (D).