Question: What set of numbers represents the union of sets A and B?
Set A {2, 15, 27, 33, 59, 65}
Set B {1, 3, 15, 59}
(a) {15, 59}
(b) {1, 2, 3, 27, 33, 65}
(c) {1, 2, 3, 15, 15, 27, 33, 59, 59, 65}
(d) {1, 2, 3, 15, 27, 33, 59, 65}
(e) {1, 2, 3, 15, 20, 27, 33, 59, 65}
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Answer:
The union of 2 sets is a set that includes all numbers that are in either set. (d) is the correct answer.
Question: If the area of a rectangle is 10 inches and its perimeter is 14 inches, what are the lengths of its sides?
(a) 2 inches and 4 inches.
(b) 2 inches and 5 inches.
(c) 3 inches and 5 inches.
(d) 3 inches and 4 inches.
(e) 2 inches and 6 inches.
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Answer: The perimeter of the rectangle is 2(a + b) and its area is ab
2(a + b) = 14
ab = 10
We can solve the system of 2 equations, or we can test the five choices and we find that a = 2 inches, b = 5 inches satisfies both equations.
Question: In the figure above, O is the center of circle C and ABO is a right triangle. If h is the hypotenuse of triangle ABO, the circumference of circle C is:
(a) (√2)¶h
(b) ¶h
(c) h/(√2)¶
(d) h2/(√2)
(e) 2¶h
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Solution: Triangle ABO is right, so according to the Pythagorean theorem,
h2 = AO2 + BO2
h2 = r2 + r2
h2 = 2r2
r = h/√2
The circumference of a circle is 2¶r = (√2)¶h