215.
A)
A= ?
B)
P= ?
C)
FV= ?
D)
PV= ?
E)
PMT= ?
216.
A)
A= 50000
B)
P= 50000
C)
FV= 50000
D)
PV= 50000
E)
PMT= 50000
217.
A)
r= 4
B)
r= 0.4
C)
r= 0.04
D)
r= .04/12
E)
r= NA
218.
A)
n=1
B)
n=4
C)
n=12
D)
n=365
E)
n= NA
219.
A)
t= 20
B)
t= 20/12
C)
t= 1
D)
t= 20/365
220. The Eisenstein’s purchase a house for $210,000. They make a down payment of 30% and borrow the rest with a
loan at 5.7% interest compounded monthly for 20 years. Their monthly mortgage payment is $1,027.87. What
was their ending balance after making one payment?
10

221. An investor wants to earn $600 in interest in one year and will invest money in two bonds.
One bond offers
a return of 12% simple interest and the other bond offers a return of 6% simple interest. If the investor has
$8,000 to invest, how much should be invested in each bond?
222. A regression analysis is done on hours of sleep (
x
) vs grade on Exam 2. The regression equation is found to be
y
= 40 + 5
x
. Determine the Exam 2 grade predicted with 3 or 10 hours of sleep.
223. Find an equation of a line through the points (1
,
4) and (5
,
−
4).
224. Find the slope of the line
y
= 6.
225. Find an equation of the line parallel to 5
x
−
4
y
= 11 that passes through the point (
−
7
,
2).
226. A student’s correct work in solving a system yields a result of:
braceleftBigg
x
+ 2
y
= 5
0
= 1
What does this mean?
227. A linear system has nonzero constants
a,b,c
and
d
, as below. What relationship between the values of
a,b,c
and
d
make the solution of the system be one solution?
braceleftBigg
y
=
ax
+
b
y
=
cx
+
d
228. Determine which of the following are solutions of the system below. Choose all that apply:
braceleftBigg
3
x
−
4
y
<
10
−
x
+ 5
y
≥
12
A)
(1,1)
B)
(0,0)
C)
(-2,4)
D)
(1,5)
E)
(-5,3)
229. At $.20 per selfie, 20 selfies are supplied and 50 are demanded. At $.50 per selfie, 80 are supplied and 20 are
demanded. Assuming selfie supply and demand is linear, find the price-demand equation for the selfies.
230. The result of RREF produced the following matrix. What is the solution of the system?
1
0
2
0
0
1
0
5
0
0
0
0
231. Davenport Dairy Farms must lease a fleet of 24 refrigerated over-the-road tanks to transport 520,000 gallons of
milk. Refrigerated tanks with three different carrying capacities are available for lease: 8,000 gallons, 16,000
gallons, and 24,000 gallons. How many of each type of tanks should be leased?
232. Solve the system
2
x
1
+
x
2
+ 3
x
3
= 9
x
1
−
x
2
−
3
x
3
=
−
6
−
2
x
1
+ 5
x
2
+ 6
x
3
= 6
11

233. A company makes and sells widgets. It costs $5 to produce and ship each widget. Each widget sells for a price
of $9. Each monthly, company has to pay $20,000 for rent, electricity and salaries. Find the cost function.
12

Solutions to Sample Exam A:
1
. Yes. Either plug in
x
=
−
1 or solve the equation to see this.
2
.
F
=
S
−
Mb
1
−
b
or equivalent.
3
.
−
22
4
. Anything in which there the solution depends on some particular values of the variable and is not always true.
For instance,
x
= 4 or 3
y
= 15 are conditional equations. Answers will vary.
5
. 19.44 years. If the problem suggested she had to wait until the end of the year to receive interest, then the answer
would have been 20 years.

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