Question: In each series, look for the degree and direction of change between the numbers. In other words, do the numbers increase or decrease, and by how much? Look at this series: 5, 43, 15, 33, 25, ...What number should come next?
Options:
(A) 10
(B) 40
(C) 23
(D) 13
(E) 20
Answer: C
23
This is an alternating addition and subtraction series. In the first pattern, 10 is added to each number to arrive at the next. In the second, 10 is subtracted from each number to arrive at the next.
The answer is (C).

Question: What will come in place of the x in the following Number series? 11, 14, 19, 22, 27, 30, 35, x
Options:
(A) 29
(B) 31
(C) 23
(D) 35
(E) 38
Answer: The pattern is + 3, + 5, + 3, + 5,
So the missing term is = 35 + 3 = 38.
The answer is (E).

Question: A wheel rotates 20 times every minute and moves 35 cm during each rotation. How many metres does the wheel move in one hour?
Options:
(A) 6 metre
(B) 120 metre
(C) 220 metre
(D) 1200 metre
(E) 420 metre
Answer: Number of times wheel moves in 1 hour = 20 * 60 = 1200
:. Distance moves = (1200*35) cms = 42000 cms
In metres = 420 metr
The answer is (E).

Question: At 15:00 there were 20 students in the computer lab. At 15:03 and every three minutes after that, 3 students entered the lab. If at 15:10 and every ten minutes after that 9 students left the lab, how many students were in the computer lab at 15:44 ?
Options:
(A) 7
(B) 14
(C) 25
(D) 27
(E) 30
Answer:
Initial no of students + 3 * (1 + No of possible 3 minute intervals between 15:03 and 15:44) -
8 *(1 + No of possible 10 minute intervals between 15:10 and 15:44)
20 + 3*14 -8 * 4 = 25
The answer is (C).