Question: What is the % change in the area of a rectangle when its length increases by 20% and its width decreases by 20%?
Options:
(A) 0%
(B) 20% increase
(C) 20% decrease
(D) 4% decrease
(E) Insufficient data
Answer: (12/10)*(8/10) = 96/100 of original area
96/100 is a 4% decrease from 100/100 ->
The answer is (D).

Question: A frame 2 inches wide is placed around a rectangular picture with dimensions 8 inches by 12 inches. What is the area of the frame, in square inches?
Options:
(A) 44
(B) 96
(C) 128
(D) 144
(E) 168
Answer: A frame 2 inches wide is placed around a rectangular picture with dimensions 8 inches by 12 inches. What is the area of the frame, in square inches?
(12*16)-(8*12) = 96
The answer is (B).

Question: A car finishes a journey in ten hours at the speed of 80 km/hr. If the same distance is to be covered in eight hours how much more speed does the car have to gain?
Options:
(A) 8 km/hr
(B) 10 km/hr
(C) 12 km/hr
(D) 16 km/hr
(E) None of these
Answer: Distance covered by the car = 80 10 = 800 km
\ Speed = 8008 = 100 km/hr
\ Speed gain = 100 80 = 20 km/hr
The answer is (E).

Question: Pipe A can fill a tank in 5 hours, pipe B in 10 hours and pipe C in 30 hours. If all the pipes are open, in how many hours will the tank be filled?
Options:
(A) 2
(B) 2.2
(C) 3
(D) 3.5
(E) 4
Answer:
Part filled by A + B + C in 1 hour = 1/5 + 1/10 + 1/30 = 1/3
All the three pipes together will fill the tank in 3 hours.
The answer is (C).