Success TutoringWorksheets

Year 12 Simple and Compound Interest Worksheet — Level 3 — Practice Set 3 — Answers

Answer sheet with worked solutions for the Year 12 financial mathematics worksheet.

Download answers PDFPrint answersBack to worksheet
Success TutoringWorksheetsAnswer sheetYear 12 · Mathematics · Financial Mathematics

Year 12 Simple and Compound Interest Worksheet — Level 3 — Practice Set 3 — Answers

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

1.$3,250.00 is invested at 8% per year, compounded yearly, for 7 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $5,569.93; interest $2,319.93

  1. A = P(1 + r)n = $3,250.00 × (1 + 0.08)7
  2. = $3,250.00 × 1.713824
  3. ≈ $5,569.93
  4. Interest = $5,569.93 − $3,250.00 = $2,319.93
2.Compare $13,000.00 invested for 5 years at 3% per year as simple interest and as interest compounded yearly. How much more does compound interest earn, to the nearest cent?

Answer: $120.56

  1. Simple: I = $13,000.00 × 0.03 × 5 = $1,950.00
  2. Compound: A = $13,000.00 × 1.035 ≈ $15,070.56, so interest ≈ $2,070.56
  3. Difference = $2,070.56 − $1,950.00 = $120.56
3.Compare $5,000.00 invested for 8 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: $242.85

  1. Simple: I = $5,000.00 × 0.04 × 8 = $1,600.00
  2. Compound: A = $5,000.00 × 1.048 ≈ $6,842.85, so interest ≈ $1,842.85
  3. Difference = $1,842.85 − $1,600.00 = $242.85
4.Compare $14,000.00 invested for 4 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: $138.02

  1. Simple: I = $14,000.00 × 0.04 × 4 = $2,240.00
  2. Compound: A = $14,000.00 × 1.044 ≈ $16,378.02, so interest ≈ $2,378.02
  3. Difference = $2,378.02 − $2,240.00 = $138.02
5.$14,500.00 is invested at 6% per year, compounded yearly, for 10 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $25,967.29; interest $11,467.29

  1. A = P(1 + r)n = $14,500.00 × (1 + 0.06)10
  2. = $14,500.00 × 1.790848
  3. ≈ $25,967.29
  4. Interest = $25,967.29 − $14,500.00 = $11,467.29
6.Compare $7,500.00 invested for 5 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: $286.69

  1. Simple: I = $7,500.00 × 0.06 × 5 = $2,250.00
  2. Compound: A = $7,500.00 × 1.065 ≈ $10,036.69, so interest ≈ $2,536.69
  3. Difference = $2,536.69 − $2,250.00 = $286.69
7.$10,750.00 is invested at 6% per year, compounded yearly, for 10 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $19,251.61; interest $8,501.61

  1. A = P(1 + r)n = $10,750.00 × (1 + 0.06)10
  2. = $10,750.00 × 1.790848
  3. ≈ $19,251.61
  4. Interest = $19,251.61 − $10,750.00 = $8,501.61
8.Compare $10,750.00 invested for 10 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: $1,106.92

  1. Simple: I = $10,750.00 × 0.045 × 10 = $4,837.50
  2. Compound: A = $10,750.00 × 1.04510 ≈ $16,694.42, so interest ≈ $5,944.42
  3. Difference = $5,944.42 − $4,837.50 = $1,106.92
Free worksheets at worksheets.successtutoring.com · © Success Tutoring · Free for personal and classroom use

Marking tips

  • Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
  • For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
  • Celebrate what went well first, then pick one thing to work on next.