Answer Key
Chapter 5 – Applying Percents 5.1
Recognize and Write Percents
Answers 1. 64/100
2. 3/100
3. 119/100
4. 4.7/100
5. 88/100
6. 99.5/100
7. 12/100
8. 14/100
9. 12%
10. 13.5%
11. 87%
12. 99%
13. 5%
14. 3.5%
15. 130%
16. 175%
5.2
Write Percents as Decimals
Answers 1. .18
2. .357
3. .0609
4. .00008
5. .00028
6. .009
7. .315
8. .123
9. 52%
10. 2%
11. 117%
12. 500%
13. 9%
14. 87.6%
15. 30%
16. .01%
5.3
Write Percents as Fractions
Answers 1. 4/25
2. 2/5
3. 1/50
4. 1/25
5. 9/20
6. 1/5
7. 9/50
8. 1/10
9. 67%
10. 77%
11. 5%
12. 1050%
13. 80%
14. 60%
15. 12%
5.4
Find the Percent of a Number
Answers 1. 27
2. .36
3. 126
4. 32.67
5. 18
6. 5.76
7. 5.5
8. 4.35
9. 9.6
10. 16
11. 31.5
12. 27
13. 6/100
14. 150
15. 80%
CK‐12 Middle School Math Concepts ‐ Grade 8
1
Answer Key
Chapter 5 – Applying Percents 5.5
Use Proportions to Find Percents
Answers 1. 46.7%
2. 1.36%
3. 94.1%
4. 75%
5. 60%
6. 20%
7. 27%
8. 72%
9. 75%
10. 1.7%
11. 50%
12. 7.3%
13. 49.5%
14. 30.3%
15. 4.1%
5.6
Use Proportions to Solve Percent Problems
Answers 1. 19.55
2. 105
3. 3.05
4. 3
5. 2
6. 61,750
7. 400
8. 810.8 or 811
9. 1.18
10. 3.03
11. 4
12. $2228.57
13. 26.25
14. 2400 pounds
15. 15%
5.7
Use the Percent Equation to Find Part a
Answers 1. 11
2. 3.5
3. 120,000
4. 5.4
5. 12.3
6. 57
7. 9.5
8. 85
9. 222.8
10. 21
11. 105.1
12. 7.7
13. 6.3
14. 1.8
15. 3.6
5.8
Use the Percent Equation to Find the Percent
Answers 1. 13.7%
2. 94%
3. 86%
4. 44%
5. 49%
6. 14%
7. 17%
8. 38%
9. 33.4%
10. 25%
11. 3%
12. 76%
13. 37%
14. 50%
15. 61%
CK‐12 Middle School Math Concepts ‐ Grade 8
2
Answer Key
Chapter 5 – Applying Percents 5.9
Use the Percent Equation to Find the Base,b
Answers 1. 255.6
2. 28.6
3. 707.3
4. 725
5. 72.5
6. 13.4
7. 1650
8. 155.6
9. 74.6
10. 73.3
11. 50
12. 68.7
13. 141.8
14. 133.3
15. 1812.5
5.10
Find the Percent of Increase
Answers 1. 71%
2. 61%
3. 35%
4. 88%
5. 15%
6. 11%
7. 21%
8. 44%
9. 25%
10. 68%
11. 33%
12. 9%
13. 3%
14. 49%
15. 2%
5.11
Find the Percent of Decrease
Answers 1. 53%
2. 75%
3. 17%
4. 13%
5. 33%
6. 11%
7. 60%
8. 95%
9. 55%
10. 41%
11. 4%
12. 29%
13. 50%
14. 95%
15. 21%
5.12
Find the Percent of Change
Answers 1. 156
2. 58
3. 14
4. 5858
5. 83
6. 31
7. 114
8. 37
9. 70
10. 630
11. 984
12. 884
13. 792
14. 653
15. 701
CK‐12 Middle School Math Concepts ‐ Grade 8
3
Answer Key
Chapter 5 – Applying Percents 5.13
Find the Retail Prices Given Wholesale, Markups and Sales Tax
Answers 1. $8.87
2. $1040.40
3. $.34
4. $82.62
5. $417.95
6. $9.43
7. $46.79
8. $382.95
9. $4.82
10. $160.95
11. $85.08
12. $35.41
13. $60.05
14. $196.18
15. $279.00
5.14
Find Discount Prices Given Sales
Answers 1. $94.35
2. $98.64
3. $102.92
4. $107.21
5. $90.06
6. $1578.98
7. $66.67
8. $58.14
9. $82.21
10. $126
11. $101.49
12. $159.96
13. $259.53
14. $60.75
15. $47.40
5.15
Solve Statistics Based Problems Involving Percents
Answers 1. 409%
2. 313%
3. 400%
4. 455%
5. 180%
6. 200%
7. 133%
8. .6%
9. .3%
10. 16.7%
11. 40%
12. 20%
13. 6.5%
14. .75%
15. 3%
5.16
Solve Percent Problems Involving Scientific Notation
Answers 1. 2.17 x 108
2. 4.55 x 1012
3. 1.134 x 10‐16
4. 2.16 x 10‐1
5. 1.2408 x 10‐1
6. 2.52 x 10‐6
7. 2.997 x 1011
8. .0000177
9. .0000112
10. .0008
11. 22.72
12. .00013
13. .0050
14. .0000027
15. 482,160,000,000
CK‐12 Middle School Math Concepts ‐ Grade 8
4
Answer Key
Chapter 5 – Applying Percents 5.17
Solve Real World Problems Involving Simple Interest
Answers 1. $45,790.50
2. $2469.60
3. $240
4. $1,656
5. $3080
6. $100.00
7. $189
8. $360
9. $504
10. $228
11. $60,264.50
12. $9212
13. $9440
14. $21,600
15. $28,750
16. $4,050
17. $14,400
18. $14,400
19. $9,300
20. $34,100
5.18
Solve Real World Problems Involving Compound Interest
Answers 1. $300
2. $960
3. $2500
4. $7500
5. $3000
6. $13,800
7. $2400
8. $24,000
9. $3120
10. $5150
11. $12,240
12. $35,700
13. $18,540
14. $8112
15. $8755
CK‐12 Middle School Math Concepts ‐ Grade 8
5
