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Year 9 Simple and Compound Interest Worksheet — Level 3 — Practice Set 2 — Answers

Answer sheet with worked solutions for the Year 9 financial mathematics worksheet.

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Success TutoringWorksheetsAnswer sheetYear 9 · Mathematics · Financial Mathematics

Year 9 Simple and Compound Interest Worksheet — Level 3 — Practice Set 2 — Answers

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

1.Compare $12,250.00 invested for 2 years at 5% per year as simple interest and as interest compounded yearly. How much more does compound interest earn, to the nearest cent?

Answer: $30.63

  1. Simple: I = $12,250.00 × 0.05 × 2 = $1,225.00
  2. Compound: A = $12,250.00 × 1.052 ≈ $13,505.63, so interest ≈ $1,255.63
  3. Difference = $1,255.63 − $1,225.00 = $30.63
2.$4,000.00 is invested at 3% per year, compounded yearly, for 5 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $4,637.10; interest $637.10

  1. A = P(1 + r)n = $4,000.00 × (1 + 0.03)5
  2. = $4,000.00 × 1.159274
  3. ≈ $4,637.10
  4. Interest = $4,637.10 − $4,000.00 = $637.10
3.$8,750.00 is invested at 2% per year, compounded yearly, for 10 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $10,666.20; interest $1,916.20

  1. A = P(1 + r)n = $8,750.00 × (1 + 0.02)10
  2. = $8,750.00 × 1.218994
  3. ≈ $10,666.20
  4. Interest = $10,666.20 − $8,750.00 = $1,916.20
4.$9,500.00 is invested at 2% per year, compounded yearly, for 6 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $10,698.54; interest $1,198.54

  1. A = P(1 + r)n = $9,500.00 × (1 + 0.02)6
  2. = $9,500.00 × 1.126162
  3. ≈ $10,698.54
  4. Interest = $10,698.54 − $9,500.00 = $1,198.54
5.$7,750.00 is invested at 4.5% per year, compounded yearly, for 7 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $10,546.68; interest $2,796.68

  1. A = P(1 + r)n = $7,750.00 × (1 + 0.045)7
  2. = $7,750.00 × 1.360862
  3. ≈ $10,546.68
  4. Interest = $10,546.68 − $7,750.00 = $2,796.68
6.Compare $2,500.00 invested for 9 years at 6% per year as simple interest and as interest compounded yearly. How much more does compound interest earn, to the nearest cent?

Answer: $373.70

  1. Simple: I = $2,500.00 × 0.06 × 9 = $1,350.00
  2. Compound: A = $2,500.00 × 1.069 ≈ $4,223.70, so interest ≈ $1,723.70
  3. Difference = $1,723.70 − $1,350.00 = $373.70
7.$11,000.00 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 $16,252.01; interest $5,252.01

  1. A = P(1 + r)n = $11,000.00 × (1 + 0.05)8
  2. = $11,000.00 × 1.477455
  3. ≈ $16,252.01
  4. Interest = $16,252.01 − $11,000.00 = $5,252.01
8.Compare $13,000.00 invested for 7 years at 8% per year as simple interest and as interest compounded yearly. How much more does compound interest earn, to the nearest cent?

Answer: $1,999.72

  1. Simple: I = $13,000.00 × 0.08 × 7 = $7,280.00
  2. Compound: A = $13,000.00 × 1.087 ≈ $22,279.72, so interest ≈ $9,279.72
  3. Difference = $9,279.72 − $7,280.00 = $1,999.72
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