q: A, B, C, and D are four points, any three of which are non-collinear. Then, the number of ways to construct three lines each joining a pair of points so that the lines do not form a triangle is
Options:
(A) 7
(B) 8
(C) 9
(D) 24
(E) 23
a: OK... To construct 2 lines, three points can be selected out of 4 in 4 x 3 x 2 = 24 ways. Now, if third line goes from the third-point to the first point, a triangle is formed, and if it goes to the fourth point, a triangle is not formed. So, there are 24 ways to form a triangle and 24 ways of avoiding triangle.
The answer is (D).

q: A shopkeeper sells his goods at cost price but uses a weight of 800 gm instead of kilogram weight. What is his profit percentage?
Options:
(A) 25%
(B) 18%
(C) 20%
(D) 40%
(E) 45%
a: OK... 100(1000-800)/800 = 25%
Profit percentage = 25%
The answer is (A).

q: If the personal income tax rate is lowered from 40% to 33%, what is the differential savings for a tax payer having an annual income before tax to the tune of $45000?
Options:
(A) $3500
(B) $5000
(C) $3150
(D) $7000
(E) $10000
a:
OK... Saving = (40-33)% of 45000 = 3150.
The answer is (C).