Reasoning: It doesn't matter which type of card you choose, so:
Probability of choosing 1st card: 1
Probability of choosing 2nd card of the same type: 5/17
Probability of choosing 3rd card of the same type: 4/16
Probability of choosing 4th marble of the same type: 3/15
Multiply and you get 1/68
Ans: (A)
Question: A marble shop contains 6 blue marbles, 6 red marbles, and 6 green marbles. If 4 marbles are purchased at random from the shop, what is the probability that the 4 marbles will be the same color?
Options:
(A) 1/68
(B) 60/68
(C) 13/68
(D) 13/48
(E) 1/48
Rationale: Speed downstream = d/t = 95/(2 1/2) = 38 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (38 - 18)/2 = 10 kmph
The answer: (A)
Question: A man rows his boat 95 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?
Options:
(A) 10 kmph
(B) 6 kmph
(C) 5 kmph
(D) 8 kmph
(E) 7 kmph
Reasoning: Dollars needed for first 100 copies = d
Dollars needed for each successive copy = e
Cost of 125 copies = cost of 100 copies + cost of 25 copies = d + 25e
Ans: (D)
Question: If it costs d dollars to make the first 100 copies of a poster and e dollars for each poster after that, what is the total cost of 125 posters?
Options:
(A) 25d + 100e
(B) 100d + 25e
(C) 125de
(D) d + 25e
(E) 125/(de)
Rationale: The total possibilities are W@W@W@ (or) @W@W@W, where 2 blue and 1 red flowers occupy the space marked as @. Hence, the Total number of permutations is 2 x (3! / 2!) = 6.
The answer: (A)
Question: One red flower, three white flowers and two blue flowers are arranged in a line such that
I. No two adjacent flowers are of the same colour.
II. The flowers at the two ends of the line are of different colours.
In how many different ways can the flowers be arranged?
Options:
(A) 6
(B) 4
(C) 10
(D) 12
(E) 14
Reasoning: D = 110 + 150 = 260
S = 36 * 5/18 = 10 mps
T = 260/10 = 26 sec
Ans: (E)
Question: How many seconds will a train 110 meters long take to cross a bridge 150 meters long if the speed of the train is 36 kmph?
Options:
(A) 28 sec
(B) 23 sec
(C) 24 sec
(D) 25 sec
(E) 26 sec
Reasoning: 252 = 2 x 2 x 3 x 3 x 7.
Ans: (A)
Question: 252 can be expressed as a product of primes as :
Options:
(A) 2 x 2 x 3 x 3 x 7
(B) 2 x 2 x 2 x 3 x 7
(C) 3 x 3 x 3 x 3 x 7
(D) 2 x 3 x 3 x 3 x 7
(E) 2 x 3 x 7 x 3 x 2