(y^n - b^n) is completely divisible by (y - b), when
Options:
(A) n is odd natural number
(B) n is even natural number
(C) n is any natural number
(D) n is prime
(E) None
Answer and stream of consciousness: (C)
Stream of consciousness: For every natural number n, (y^n - b^n) is completely divisible by (y - b).


The Average of six numbers is 8. The average of the first two is 11 and the average of the last three is 4. What is the middle number?
Options:
(A) A) 15
(B) B) 8
(C) C) 6
(D) D) 14
(E) E) 9
Answer and stream of consciousness: (D)
Stream of consciousness: The total of six numbers = 6X8 = 48
The total of first 2 and last 3 numbers is = 2 X 11+3 X 4 = 34
So, the middle number is (48 - 34 ) = 14


There are 23 distinct numbers in set M, there are 28 distinct numbers in set N, and there are 12 distinct numbers that are in both sets M and N. Set H is the set containing the elements that are in at least one of sets M and N. How many elements are in set H?
Options:
(A) 39
(B) 40
(C) 51
(D) 58
(E) 63
Answer and stream of consciousness: (A)
Stream of consciousness: {Total} = {M} + {N} - {Both}
{Total} = 23 + 28 - 12 = 39.


A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that atleast one bulb is good.
Options:
(A) 6/63
(B) 2/63
(C) 125/126
(D) 1/126
(E) 1/63
Answer and stream of consciousness:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
(C)
Stream of consciousness: Required probability = 1 - 1/126 = 125/126