Ques: Three people took GMAT practice tests in which the minimum and maximum possible scores are 200 and 800, respectively. They each took a test 4 times, and no one scored below 450 or over 650. If the individual ranges of the three people's scores in those 4 practice tests were 30, 80 and 110, what is the difference between the maximum and minimum possible ranges of all their scores put together.
Options:
(A) 90
(B) 120
(C) 50
(D) 70
(E) 100
Ans: (A)
CoT: According to the information in the question the maximum range would be between 450 and 650(200). The minimum range would be the greatest range for any one individual, which is listed in the problem as 110. So the difference between these would be 200-110 or 90.

Ques: Two trains are moving at 90 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) 42/5 sec
(B) 45/8 sec
(C) 40/6 sec
(D) 37/6 sec
(E) 42/4 sec
Ans: (B)
CoT: 70 + 90 = 150 * 5/18 = 400/9 mps
D = 150 + 100 = 250 m
T = 250 * 9/400 = 45/8 sec

Ques: A train 210 m long, running with a speed of 63 km/hr will pass a tree in?
Options:
(A) 15 sec
(B) 16 sec
(C) 18 sec
(D) 12 sec
(E) 25 sec
Ans: (D)
CoT: Speed = 63 * 5/18 = 35/2 m/sec
Time taken = 210 * 2/35 = 12 sec

Ques: From among the 36 students in a class, one leader and one class representative are to be appointed. In how many ways can this be done?
Options:
(A) 1360
(B) 1260
(C) 1060
(D) 1160
(E) 1460
Ans: (B)
CoT: There are 36 students and every one has equal chance of being selected as a leader. Hence, the leader can be appointed in 36 ways. When one person is appointed as leader, we are left with 35 students. Out of these 35 teachers, we can select one class representative. So, a class representative can be selected in 35 ways. Hence, the number of ways in which a leader and class representative can be selected = 36 x 35 = 1260