1.
Chemistry
The pH of a solution and the concentration [H
+
] of hydrogen ions in the solution are related by the formula
. Find the concentration of hydrogen ions in a solution with a pH of 2.9.
A.
794.33
B.
0.00068
C.
0.0013
D.
0.00032
Hint
2.
Find log 47.2 to four decimal places.
A.
2.0791
B.
1.6739
C.
0.6739
D.
3.8544
Hint
3.
Solve 3
x
+ 4
= 7
x
- 1
to three decimal places.
A.
7.483
B.
1.254
C.
-1.993
D.
2.397
Hint
4.
Real Estate
Julie bought a house for $100,000 five years ago. If the value of the house has appreciated 5% per year, how much is it worth now?
A.
$125,000.00
B.
$77,378.09
C.
$127,628.16
D.
$119,643.57
Hint
5.
Radioactivity
The half-life of uranium-232 is 72 years. Find the approximate value of
k
in the formula
y
=
ne
kt
for uranium-232. Assume
t
is in years.
A.
0.0012
B.
-0.0096
C.
-0.0024
D.
-0.0048
Hint
6.
Which of the following represents exponential decay?
A.
B.
C.
D.
Hint
7.
Suppose that the wealth of a business owner is increasing exponentially. In 1993, he had $40 million. In 2001, he had $55 million. How much money will he have in 2010?
A.
$57.2 million
B.
$20.3 million
C.
$78.7 million
D.
$28.0 million
Hint
8.
Solve log
3
x
< 4. Check your solution.
A.
x
< 64
B.
0 <
x
< 81
C.
0 <
x
< 64
D.
x
< 81
Hint
9.
Solve log
27
.
A.
243
B.
45
C.
977,048
D.
59049
Hint
10.
Solve the equation 2 log
6
x
– log
6
5 = log
6
125.
A.
–25
B.
no solution
C.
312.5
D.
25
Hint
11.
Solve 3
e
-2
x
= 5.
A.
–0.26
B.
0.51
C.
0.26
D.
–0.51
Hint
12.
Solve ln (2
x
+ 3) > 4.
A.
x
> 20.2
B.
x
< 20.2
C.
x
< 25.8
D.
x
> 25.8
Hint