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9th Grade Simple and Compound Interest Worksheet — Level 3 — Practice Set 4 — Answers

Answer sheet with worked solutions for the 9th Grade financial math worksheet.

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Success TutoringWorksheetsAnswer sheet9th Grade · Mathematics · Financial Mathematics

9th Grade Simple and Compound Interest Worksheet — Level 3 — Practice Set 4 — Answers

Show your work. Write the rate as a decimal (5% = 0.05). Round money to the nearest cent.

1.Compare $9,500.00 invested for 2 years at 4.5% per year as simple interest and as interest compounded yearly. How much more does compound interest earn, to the nearest cent?

Answer: $19.24

  1. Simple: I = $9,500.00 × 0.045 × 2 = $855.00
  2. Compound: A = $9,500.00 × 1.0452 ≈ $10,374.24, so interest ≈ $874.24
  3. Difference = $874.24 − $855.00 = $19.24
2.$13,500.00 is invested at 6% per year, compounded yearly, for 3 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $16,078.72; interest $2,578.72

  1. A = P(1 + r)n = $13,500.00 × (1 + 0.06)3
  2. = $13,500.00 × 1.191016
  3. ≈ $16,078.72
  4. Interest = $16,078.72 − $13,500.00 = $2,578.72
3.$13,250.00 is invested at 8% per year, compounded yearly, for 9 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $26,486.81; interest $13,236.81

  1. A = P(1 + r)n = $13,250.00 × (1 + 0.08)9
  2. = $13,250.00 × 1.999005
  3. ≈ $26,486.81
  4. Interest = $26,486.81 − $13,250.00 = $13,236.81
4.$12,000.00 is invested at 3% per year, compounded yearly, for 10 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $16,127.00; interest $4,127.00

  1. A = P(1 + r)n = $12,000.00 × (1 + 0.03)10
  2. = $12,000.00 × 1.343916
  3. ≈ $16,127.00
  4. Interest = $16,127.00 − $12,000.00 = $4,127.00
5.$5,500.00 is invested at 3% per year, compounded yearly, for 3 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $6,010.00; interest $510.00

  1. A = P(1 + r)n = $5,500.00 × (1 + 0.03)3
  2. = $5,500.00 × 1.092727
  3. ≈ $6,010.00
  4. Interest = $6,010.00 − $5,500.00 = $510.00
6.$14,500.00 is invested at 5% per year, compounded yearly, for 8 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $21,423.10; interest $6,923.10

  1. A = P(1 + r)n = $14,500.00 × (1 + 0.05)8
  2. = $14,500.00 × 1.477455
  3. ≈ $21,423.10
  4. Interest = $21,423.10 − $14,500.00 = $6,923.10
7.$1,000.00 is invested at 3% per year, compounded yearly, for 9 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $1,304.77; interest $304.77

  1. A = P(1 + r)n = $1,000.00 × (1 + 0.03)9
  2. = $1,000.00 × 1.304773
  3. ≈ $1,304.77
  4. Interest = $1,304.77 − $1,000.00 = $304.77
8.Compare $11,750.00 invested for 7 years at 4% per year as simple interest and as interest compounded yearly. How much more does compound interest earn, to the nearest cent?

Answer: $422.20

  1. Simple: I = $11,750.00 × 0.04 × 7 = $3,290.00
  2. Compound: A = $11,750.00 × 1.047 ≈ $15,462.20, so interest ≈ $3,712.20
  3. Difference = $3,712.20 − $3,290.00 = $422.20
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