Find the area of trapezium whose parallel sides are 20 cm and 18 cm long, and the distance between them is 15 cm.
Options:
(A) 225 cm2
(B) 275 cm2
(C) 285 cm2
(D) 315 cm2
(E) None of these

Area of a trapezium = 1/2 (sum of parallel sides) * (perpendicular distance between them) = 1/2 (20 + 18) * (15) = 285 cm2 So the answer is: (C).

Two persons A and B can complete a piece of work in 30 days and 60 days respectively. If they work together, what part of the work will be completed in 10 days?
Options:
(A) 1/8
(B) 1/3
(C) 1/6
(D) 1/2
(E) 5/3

A's one day's work = 1/30
B's one day's work = 1/60
(A + B)'s one day's work = 1/30 + 1/60 = 1/20
The part of the work completed in 10 days = 10 (1/20) = 1/2. So the answer is: (D).

Which of the following CANNOT be weighed using a balance scale and these unit weights: 2, 4, 7, and 10
Options:
(A) 16
(B) 15
(C) 18
(D) 19
(E) 21

A. 13 (can be weighed by keeping weights of 10, 2 and 4 )
B. 15 (cannot be weighed)
C. 17 (can be weighed by keeping weights of 10 and 7 kg)
D. 19(can be weighed by keeping weights of 10, 2 and 7 kg)
E. 21 (can be weighed by keeping weights of 10, 7 and 4 kg) So the answer is: (B).

If six persons sit in a row, then the probability that three particular persons are always together is?
Options:
(A) 1/5
(B) 1/4
(C) 1/9
(D) 1/6
(E) 1/1


Six persons can be arranged in a row in 6! ways. Treat the three persons to sit together as one unit then there four persons and they can be arranged in 4! ways. Again three persons can be arranged among them selves in 3! ways. Favourable outcomes = 3!4! Required probability = 3!4!/6! = 1/5 So the answer is: (C).