q: Two trains are moving at 50 kmph and 70 kmph in opposite directions. Their lengths are 150 m and 100 m respectively. The time they will take to pass each other completely is?
Options:
(A) 7 1/9
(B) 7 1/8
(C) 7 1/3
(D) 7 1/2
(E) 7 1/1
a: Stream of consciousness: 70 + 50 = 120 * 5/18 = 100/3 mps
D = 150 + 100 = 250 m
T = 250 * 3/100 = 15/2 = 7 1/2 sec The answer is (D).
--
q: Preethi has 6 flavors of ice cream in his parlor. How many options are there for Dorathy to pick a one-flavor, two-flavor, three-flavor, four-flavor, five flavor or six flavor order?
Options:
(A) 26
(B) 36
(C) 64
(D) 67
(E) 63
a: Stream of consciousness: 6C1 + 6C2+ 6C3+6C4+6C5+6C6 = 63. The answer is (E).
--
q: (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
a:

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
Stream of consciousness: For every natural number n, (y^n - b^n) is completely divisible by (y - b). The answer is (C).
--