Worked-out Problems
Worked-out Problems
Worked-out Problems
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Chapter 3 continued<br />
42. 6.3a > 10.71<br />
6 .3a<br />
6.3<br />
> 10 . 71<br />
6 <br />
. 3<br />
a > 1.7<br />
1 1.2 1.4 1.6 1.8 2<br />
43. 3.9c ≤ 43.68<br />
3.<br />
3<br />
9c<br />
. 9<br />
≥ 4 3.68<br />
<br />
3.9<br />
c ≥ 11.2<br />
12 11.8 11.6 11.4 11.2 11<br />
y<br />
44. ≤ 6.5 9.1<br />
y<br />
9.1 p ≥ 9.1 p 6.5<br />
9.1<br />
y ≥ 59.15<br />
60 59.8 59.6 59.4 59.2 59<br />
45. Let x the number of minutes spent in the shower.<br />
Gallons per minute Number of Gallons used<br />
p <<br />
used in shower minutes in shower in bathtub<br />
2x < 60<br />
2 x<br />
< 6 0<br />
<br />
2 2<br />
x < 30<br />
You can be in the shower for less than 30 minutes.<br />
46. a. d ≥ rt<br />
36 ≥ r p 24<br />
3 6<br />
≥ 2 4r<br />
<br />
24<br />
24<br />
1.5 ≥ r<br />
Caribou can migrate 1.5 miles per hour or less.<br />
b. 3 days 72 hours<br />
72 hours p 1.5 m iles<br />
108 miles<br />
hour<br />
47. A lw 10(12) 120<br />
The area of your room is 120 square feet.<br />
Let x the cost per square foot of carpeting.<br />
Number of<br />
square feet<br />
104 106 108<br />
p<br />
59.15<br />
Cost per<br />
square feet<br />
≤<br />
120x ≤ 200<br />
110<br />
Maximum<br />
amount<br />
1 20<br />
12<br />
x<br />
0<br />
≤ 2 0<br />
1 <br />
0<br />
20<br />
x ≤ 1.66<br />
Your parents will spend a maximum of $1.66 per<br />
square foot.<br />
48. Sample answer: 6x < 9 is equivalent to 2x < 3 and 4x < 6.<br />
49. Let P the water pressure.<br />
Let d the depth underwater in feet.<br />
P ≥ 14.7 0.45d<br />
1500 ≥ 14.7 0.45d<br />
1500 14.7 ≥ 14.7 0.45d 14.7<br />
1485.3 ≥ 0.45d<br />
14 85<br />
0.4<br />
.3<br />
5<br />
≥ 0 .45d<br />
0 <br />
.45<br />
3300 2 3 ≥ d<br />
The camera can be used at a depth at or above 3300 2 3 feet.<br />
3.5 Mixed Review (p. 148)<br />
50. x 3.5 9.2<br />
x 3.5 3.5 9.2 3.5<br />
x 5.7<br />
Check: x 3.5 9.2<br />
5.7 3.5 9.2<br />
9.2 9.2 ✓<br />
51. x 6.7 5.8<br />
x 6.7 6.7 5.8 6.7<br />
x 12.5<br />
Check: x 6.7 5.8<br />
12.5 6.7 5.8<br />
5.8 5.8 ✓<br />
52. 44.72 5.2x<br />
44 . 7<br />
5.<br />
2<br />
2<br />
5 . 2x<br />
5 <br />
. 2<br />
8.6 x<br />
Check: 44.72 5.2x<br />
44.72 5.2(8.6)<br />
44.72 44.72 ✓<br />
53. 7<br />
x<br />
.6 9.5<br />
x<br />
7.6 p 7.6 p 9.5<br />
7 .6<br />
x 72.2<br />
x<br />
Check: 7 .6 9.5<br />
7 2.<br />
2<br />
<br />
7.<br />
6<br />
9.5<br />
9.5 9.5 ✓<br />
Copyright © McDougal Littell/Houghton Mifflin Company<br />
All rights reserved.<br />
Chapter 3<br />
Pre-Algebra 97<br />
<strong>Worked</strong>-Out Solution Key
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