Selected Answers and Solutions R15Selected Answers and Solutions
For Homework Help, go to Hotmath.comSo, 21% of 90 is about 18.
Method 2 Use 10% to estimate.
10% of 90 is 9.
21% is about 2 × 10%.
2 × 9 = 18.
So, 21% of 90 is about 18.- 18; _^35 · 30 = 18; 0.1 · 30 = 3 and 6 · 3 = 18
- 12.5; _^14 · 50 = 12.5; 0.1 · 50 = 5 and 2.5 · 5 = 12.5
- 180; _ 109 · 200 = 180; 0.1 · 200 = 20 and 9 · 20 = 180
- 100; _^23 · 150 = 100; 0.1 · 150 = 15 and 6.6 · 15 ≈ 100
- about $6; _ 203 · $40 = $6 23. (1 · 50) +
(^) ( 103 · (^50) ) = 65 25. 0.01 · 400 = 4 and ^12 · 4 = 2
- 0.01 · 500 = 5 and ^25 · 5 = 2 29. about 96 mi;
0.01 · 12,000 = 120 and ^45 · 120 = 96 31.^23 _ · 9 = 6 - 31 · 90 = 30 35.^15 · 100 = 20
3737 a. Estimate 13% of 24 hours.
13% is about 10% or 101.
13% of 24 ≈ 101 · 24 or 2.4
So, 13% of 24 is about 2.4. Avery spends about 2.4
hours on homework.
b. Estimate 33% of 24.
33% is about^1 3.
33% of 24 ≈ 1 3 · 24 or 8
So, 33% of 24 is about 8. Avery spends about 8
hours sleeping.
Estimate 19% of 24.
19% is about 20% or ^15. 24 is about 25.
19% of 24 ≈ 1 5 · 25 or 5
So, 19% of 24 is about 5. Avery spends about 5
hours doing the activities in the “other” category.
Avery spends 8 - 5 or 3 hours more sleeping than
doing the activities in the “other” category.
c. There are 24 · 60 or 1,440 minutes in one day.
Estimate 8% of 1,440.
8% is about 10% or 101.
8% of 1,440 ≈ 101 · 1,440 or 144
So, 8% of 1,440 is about 144. Avery spends about
144 minutes each day on extracurricular activities.
39a. Sample answer:
10% 10% 10% 10% 10% 10% 10% 10% 10% 10%100%60 60 60 60 60 60 60 60 60 60 600passespercent39b. 420 39c. greater; Both the number of passes
and the percent were rounded up.
39d. Peyton Manning; because 65% of 515 must
be greater than 65% of 404.41a. Sample answer: about 260 canned foods;
200 + 0.3 · 130 41b. Sample answer: about 780
canned foods; 600 + 0.3 · 600 43a. Sample answer:
$75; (100% of 60) + (25% of 60) = 60 + 15 = 75
43b. Sample answer: less than; 125% < 130%- He incorrectly changed 1.5% to 1.5, which is
150%. It should be about 3. 47. Sample answer:
One way to find 22% of 136 is to find _^15 · 140 = 28.
Another way to fi nd 22% of 136 is to fi rst fi nd
(0.1 · 140) and then multiply by 2. The result is 28. - H
Pages 335–336 Lesson 6-2B- 36% 3. 0.7
55 9 is 12% of which number?
w^9 = 10012 Write the proportion.
9 · 100 = 12 · w Find the cross products.
900 = 12 w Simplify.
^90012 = ^1212 w Divide each side by 12.
75 = w
So, 9 is 12% of 75. - 3 c 9. 7.5% 11. 8.6 13. 375 15. 24 points
- 40% 19. 4.1 21. 192
2323 What percent of 300 is 0.6?
300 0.6 = 100 n Write the proportion.
0.6 · 100 = 300 · n Find the cross products.
60 = 300 n Simplify.
30060 = ^300300 n Divide each side by 300.
0.2 = n
So, 0.6 is 0.2% of 300. - 75 students; 70 of the students bought their
lunch. Some amount, x, left the cafeteria. The new
percent proportion would be 10070 - - x (^) x = 10060.
So, x = 25. 100 - 25 = 75 27. Sample answer: A
runner won 15% of the races he ran. If he won 3
races, how many races did he run? 29. F 31. 30
33a. 16% 33b. 24% 33c. 60%
Pages 339–341 Lesson 6-2C
- p = 0.88 · 300; 264
33 75 is what percent of 150?
75 = n · 150 Write the percent equation.
15075 = ^150150 n Divide each side by 150.
0.5 = n Simplify.
Since n represents the decimal form, the percent is
50%. So, 75 is 50% of 150. - 3 = 0.12 · w; 25 7. 39 loaves 9. p = 0.39 · 65;
25.4 11. p = 0.53 · 470; 249.1 13. 26 = n · 96;
27.1% 15. 30 = n · 64; 46.9% 17. 84 = 0.75 · w;
112 19. 64 = 0.8 · w; 80 21. 4,400 games - 1 lobster 25. p = 0.004 · 82.1; 0.3
- 230 = n · 200; 115%
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