[Ques]: A marble shop contains 5 blue marbles, 5 red marbles, and 5 green marbles. If 2 marbles are purchased at random from the shop, what is the probability that the 2 marbles will be of the red?
Options:
(A) 5/15
(B) 2/21
(C) 20/15
(D) 5/210
(E) 4/14
*Ans*: (B)
--CoT--: Of the 15 marbles we are wanting red:
Probability of choosing 1st red marble: 5/15
Probability of Choosing 2nd red marble: 4/14
Multiply and you get 20/210 simplified to 2/21

[Ques]: A person spends 1/3rd of the money with him on clothes, 1/5th of the remaining on food and 1/4th of the remaining on travel. Now, he is left with Rs 300. How much did he have with him in the beginning?
Options:
(A) s 200
(B) s 750
(C) s 300
(D) s 450
(E) s 550
*Ans*: (B)
--CoT--: Suppose the amount in the beginning was Rs 'x'
Money spent on clothes = Rs 1x/3 Balance = Rs 2x/3
Money spent on food = 1/5 of 2x/3 = Rs 2x/15
Balance = 2x/3 - 2x/15 = Rs 8x/15
Money spent on travel = 1/4 of 8x/15 = Rs 2x/15 = 8x/15 - 2x/15 = 6x/15 = Rs2x/5
Therefore 2x/5 = 300 = 750

[Ques]: The floor of a rectangular room is 20 m long and 12 m wide. The room is surrounded by a veranda of width 2 m on all its sides. The area of the veranda is :
Options:
(A) 144 m2
(B) 120 m2
(C) 108 m2
(D) 158 m2
(E) None of these
*Ans*: (A)
--CoT--: Area of the outer rectangle = 24 16 = 384 m2
Area of the inner rectangle = 20 12 = 240 m2
Required area = (304 180) = 144 m2

[Ques]: A 160 meter long train crosses a man standing on the platform in 16 sec. What is the speed of the train?
Options:
(A) 36 kmph
(B) 54 kmph
(C) 92 kmph
(D) 86 kmph
(E) 76 kmph
*Ans*: (A)
--CoT--: S = 160/16 * 18/5 = 36 kmph