Ques: A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
Options:
(A) 12 days
(B) 15 days
(C) 18 days
(D) 20 days
(E) 22 days
Ans: (C)
CoT: A’s two day’s work = 2/20 = 1/10
(A + B + C)’s one day’s work = 1/20 + 1/30 + 1/60 = 6/60 = 1/10
Work done in 3 days = (1/10 + 1/10) = 1/5
Now, 1/5 work is done in 3 days
Therefore, Whole work will be done in (3 x 5) = 15 days.

Ques: A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?
Options:
(A) 40 sec
(B) 42 sec
(C) 45 sec
(D) 48 sec
(E) 58 sec
Ans: (A)
CoT: Speed = 45 * 5/18 = 25/2 m/sec
Total distance covered = 360 + 140 = 500 m
Required time = 500 * 2/25 = 40 sec

Ques: Henry earns $120 a week from his job. His income increased and now makes $180 a week. What is the percent increase?
Options:
(A) 70%
(B) 60%
(C) 50%
(D) 40%
(E) 30%
Ans: (C)
CoT: Increase = (60/120)*100 = (1/2)*100 = 50%.

Ques: An design manager has 10patterns of chairs & 7patterns of tables. In how many ways can he make a pair of table & chair?
Options:
(A) 70
(B) 40
(C) 80
(D) 90
(E) 100
Ans: (A)

CoT: He has has ten patterns of chairs and eight patterns of tables
Hence, A chair can be arranged in 10 ways and
A table can be arranged in 7 ways
Hence one chair and one table can be arranged in 10 x 7 ways = 70 ways