12.Practice.Tests.for.the.SAT_2015-2016_1128p

12 Practice Tests for the SAT
834 Practice Test Nine Answers and Explanations
If there are 2 ounces of alcohol left after starting with 16
ounces, then 1 6 - 2 = 1 4 ounces must have evaporated,
so the correct answer is 14, (E).
10. B
Difficulty: High
Strategic Advice: The shaded region is one of four equal
pieces left when the circle is subtracted from the square.
So to find the area of the shaded region, you must subtract
the area of the circle from the area of the square and then
take f of this difference. You must first find the area of the
circle and the area of the square. To find the area of the
circle, you must know its radius.
Getting to the Answer:
You're told that the circumference of the circle is 47t. You
also know that the circumference C of a circle is related to
its radius r by the formula C = 2w. So here, 47t = 2w and
r = 2. The area of the circle is w2, which equals 7t(2)2 or 47t.
To find the area of the square, you must know the length
of its side. If you draw in the diameter of the circle whose
endpoints are the point where the circle touches side BC
of the square and the point where the circle touches side
AD of the square, you'll see that the side of the square is
equal in length to the diameter of the circle. The radius of
the circle is 2, so its diameter, which is twice the radius, is
2 x 2 or 4. Since the side of the square is 4, its area is its
side squared or 42, which is 16. The area of the square is
16 and the area of the circle is 47t, so the area outside the
circle and inside the square is 1 6 - 47t. So the area of the
shaded region is 1 6 47t = 4 _ 7t.
11. B
Difficulty: Medium
Strategic Advice: Drawing a diagram is the key to solving
this problem.
Getting to the Answer:
Draw two parallel lines, m and n; now draw three different
transversals through them, trying to form the least number
of points of intersection.
From the diagram above, you can see that the number is
4, since the three transversals can pass through the first
parallel line at different points, yet pass through a common
point on the second parallel line.
12. D
Difficulty: Medium
Strategic Advice: Think about the graph of each answer
choice. If several look similar, or if you're not sure what an
equation should look like when graphed, try plugging in
the information given in the figure above.
Getting to the Answer:
For instance, you could use the information for the year
1 992. This is 1 992-1 980 = 12 years after the study began,
so t = 12. From the graph, d = 800. Plug these numbers
into each equation to see which one is true: (100)2 .lf =
(100)23 = (100)8 = 800, so (D) is correct.
13. E
Difficulty: Medium
Strategic Advice: Remember, the value of r(x) is shown by
the y-value of each point.
Getting to the Answer:
When r(x) = 0, the graph touches the x-axis. This graph
touches the x-axis at x = -5 and x = - 1 .
m
n