Answer: (C)
Question: If we need to change the average age of a group containing 4 persons from 40 to 38 by adding a person. What should be the age of the person newly added to the group?
Options:
(A) 20
(B) 25
(C) 30
(D) 38
(E) 40
[CoT]: [Sum of the ages of the group having 4 persons and average 40 = 4x40 = 160
Sum of the ages of the group having 5 persons and average 38 = 5x38 = 190
Age of the new person added to the group = 190-160 = 30]

Answer: (E)
Question: Grace has 18 jellybeans in her pocket. She has 10 red ones, 4 green ones, and 4 blue ones. What is the minimum number of jellybeans she must take out of her pocket to ensure that she has one of each color?
Options:
(A) 4
(B) 8
(C) 12
(D) 13
(E) 15
[CoT]: [The worst scenario is when she takes 10 red and 4 green, total of 14 jellybeans, and still doesn't have 3 distinct colors. But the next draw (15th) will surely be the third color jellybean (blue) as there is no other color jellybeans left in pocket.]

Answer: (A)
Question: A train running at the speed of 90 km/hr crosses a pole in 6 seconds. Find the length of the train.
Options:
(A) 150 meter
(B) 100 meter
(C) 105 meter
(D) 120 meter
(E) 130 meter
[CoT]: [Speed = 90*(5/18) m/sec = 25 m/sec
Length of Train (Distance) = Speed * Time
(25) * 6 = 150 meter]

Answer: (A)
Question:
A train 180 m long running at 70 kmph crosses a platform in 20 sec. What is the length of the platform?
Options:
(A) 208
(B) 277
(C) 350
(D) 881
(E) 271
[CoT]: [D = 70 * 5/18 = 20 = 388 180 = 208]