Success TutoringWorksheets

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

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

Download answers PDFPrint answersBack to worksheet
Success TutoringWorksheetsAnswer sheetYear 9 · Mathematics · Financial Mathematics

Year 9 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.Compare $15,000.00 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: $2,307.36

  1. Simple: I = $15,000.00 × 0.08 × 7 = $8,400.00
  2. Compound: A = $15,000.00 × 1.087 ≈ $25,707.36, so interest ≈ $10,707.36
  3. Difference = $10,707.36 − $8,400.00 = $2,307.36
2.Compare $1,500.00 invested for 10 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: $286.27

  1. Simple: I = $1,500.00 × 0.06 × 10 = $900.00
  2. Compound: A = $1,500.00 × 1.0610 ≈ $2,686.27, so interest ≈ $1,186.27
  3. Difference = $1,186.27 − $900.00 = $286.27
3.$12,250.00 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 $13,795.49; interest $1,545.49

  1. A = P(1 + r)n = $12,250.00 × (1 + 0.02)6
  2. = $12,250.00 × 1.126162
  3. ≈ $13,795.49
  4. Interest = $13,795.49 − $12,250.00 = $1,545.49
4.$3,750.00 is invested at 2% per year, compounded yearly, for 3 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $3,979.53; interest $229.53

  1. A = P(1 + r)n = $3,750.00 × (1 + 0.02)3
  2. = $3,750.00 × 1.061208
  3. ≈ $3,979.53
  4. Interest = $3,979.53 − $3,750.00 = $229.53
5.$14,000.00 is invested at 4.5% per year, compounded yearly, for 4 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $16,695.26; interest $2,695.26

  1. A = P(1 + r)n = $14,000.00 × (1 + 0.045)4
  2. = $14,000.00 × 1.192519
  3. ≈ $16,695.26
  4. Interest = $16,695.26 − $14,000.00 = $2,695.26
6.$6,000.00 is invested at 4.5% per year, compounded yearly, for 10 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $9,317.82; interest $3,317.82

  1. A = P(1 + r)n = $6,000.00 × (1 + 0.045)10
  2. = $6,000.00 × 1.552969
  3. ≈ $9,317.82
  4. Interest = $9,317.82 − $6,000.00 = $3,317.82
7.$6,250.00 is invested at 2% per year, compounded yearly, for 3 years. Find the final amount and the interest earned, to the nearest cent.

Answer: Amount $6,632.55; interest $382.55

  1. A = P(1 + r)n = $6,250.00 × (1 + 0.02)3
  2. = $6,250.00 × 1.061208
  3. ≈ $6,632.55
  4. Interest = $6,632.55 − $6,250.00 = $382.55
8.Compare $5,750.00 invested for 9 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: $582.64

  1. Simple: I = $5,750.00 × 0.05 × 9 = $2,587.50
  2. Compound: A = $5,750.00 × 1.059 ≈ $8,920.14, so interest ≈ $3,170.14
  3. Difference = $3,170.14 − $2,587.50 = $582.64
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.