Look at this series: 0.6, 0.3, ____, 0.075, 0.0375, ... What number should fill the blank?
Options:
(A) 0.015
(B) 1.15
(C) 0.15
(D) 0.25
(E) 0.35

This is a simple multiplication series. Each number is multiple by 1/2. So the answer is: (C).

There are different 45 circles. What is the number of the greatest possible points with which the circles intersect?
Options:
(A) 1950
(B) 2000
(C) 1980
(D) 1580
(E) 2600

Maximum points of intersection between n different circles = n*(n - 1) = 45*44 = 1980 So the answer is: (C).

5,9,20,32,52,__
Options:
(A) 79
(B) 85
(C) 81
(D) 82
(E) 83

(9+5) +6 = 20
(16+9) +7 = 32
(28+16)+8 = 52
(48+28)+9 = 85 So the answer is: (B).

A train of 24 carriages, each of 60 meters length, when an engine also of 60 meters length is running at a speed of 60 kmph. In what time will the train cross a bridge 1.3 km long?
Options:
(A) 2 mins 14 sec
(B) 2 mins 34 sec
(C) 168 sec
(D) 344 sec
(E) 2 mins 44 sec

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
D = 25 * 60 + 1300 = 2800 m
T = 2800/60 * 18/5 = 168 se So the answer is: (C).