Grade 10 Maths · Financial Maths

Use the simple interest formula

Use the simple interest formula A = P(1 + in) to find the amount, interest, rate or time, for example R1 000 at 5% for 3 years gives R1 150.

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Financial Maths Grade 10 | Simple Interest IntroductionKevinmathscience

1) Simple Interest Grade 9 | Part 1Kevinmathscience

Financial Maths Grade 10 | Simple Interest | Determine PKevinmathscience

1) Simple Interest Grade 9 | Part 3Kevinmathscience

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Question 1.2 · September 2024 · Provincial · 3 marks

An advertisement in a local newspaper reads as follows:
Buy an iPhone 14 Pro Max cell phone for only R1 029 per month. You have 36 months to pay.
• No deposit is required.

1.2 The monthly instalment quoted in the advertisement, is calculated on a hire purchase agreement which charges interest of

8, 2%

p.a. on the cash price of the cell phone. Calculate the cash price of the cell phone.(3)

Work it out on paper first. Then mark yourself with the official memo, one tick at a time.

More past paper questions: use the simple interest formula

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3. Question 4.2.2 · November 2024 · Paper 1 · Provincial · 4 marks
4.2 A television set costs R 20 000. Belinda buys it on hire purchase. She traded in an old television for R 3 000 and also paid a deposit of R 2 000. She made monthly installments of R 900 for a period of 2 years.
4.2.2 Calculate the simple interest rate.(4)
Show the memo (3 ticks)Memo
1. ✓
  Select formula and substitute $A = P (1 + ni)$
  $21600 = 15000 (1 + 2 i)$
  2 marks · Use the simple interest formula
2. ✓
  Simplify $\frac{21600}{15000} - 1 = 2 i$
  $0, 44 = 2 i$
  1 mark · Solve a linear equation
3. ✓
  Solve for rate $i = 0, 22$
  $r = 22%$
  1 mark · Use the simple interest formula
4. Question WE2 · Siyavula Grade 10 Mathematics, 9.2 Simple interest, Worked example 2 · 3 marks
WE2 Sarah borrows R5 000 from her neighbour at an agreed simple interest rate of $12, 5%$ p.a. She will pay back the loan in one lump sum at the end of $2$ years. How much will she have to pay her neighbour?(3)
Show the memo (3 ticks)Memo
1. ✓
  FormulaKnown values: $P = 5000$ ; $i = 0, 125$ ; $n = 2$
  $A = P (1 + in)$
  1 mark · Use the simple interest formula
2. ✓
  Substitution $A = 5000 (1 + 0, 125 \times 2)$
  1 mark · Use the simple interest formula
3. ✓
  Answer $A = 6250$
  At the end of $2$ years, Sarah will pay her neighbour R6 250.
  1 mark · Use the simple interest formula
5. Question WE1 · Siyavula Grade 10 Mathematics, 9.2 Simple interest, Worked example 1 · 3 marks
WE1 Carine deposits R1 000 into a special bank account which pays a simple interest rate of $7%$ p.a. for $3$ years. How much will be in her account at the end of the investment term?(3)
Show the memo (3 ticks)Memo
1. ✓
  FormulaKnown values: $P = 1000$ ; $i = 0, 07$ ; $n = 3$
  $A = P (1 + in)$
  1 mark · Use the simple interest formula
2. ✓
  Substitution $A = 1000 (1 + 0, 07 \times 3)$
  1 mark · Use the simple interest formula
3. ✓
  Answer $A = 1210$
  At the end of $3$ years, Carine will have R1 210 in her bank account.
  1 mark · Use the simple interest formula
6. Question WE3 · Siyavula Grade 10 Mathematics, 9.2 Simple interest, Worked example 3 · 4 marks
WE3 Prashant deposits R30 000 into a bank account that pays a simple interest rate of $7, 5%$ p.a. How many years must he invest for to generate R45 000?(4)
Show the memo (4 ticks)Memo
1. ✓
  FormulaKnown values: $A = 45000$ ; $P = 30000$ ; $i = 0, 075$
  $A = P (1 + in)$
  1 mark · Use the simple interest formula
2. ✓
  Substitution $45000 = 30000 (1 + 0, 075 \times n)$
  1 mark · Use the simple interest formula
3. ✓
  Value of n $\frac{45 000}{30 000} = 1 + 0, 075 \times n$
  $\frac{45 000}{30 000} - 1 = 0, 075 \times n$
  $\frac{( \frac{45 000}{30 000} ) - 1}{0 , 075} = n$
  $n = 6 \frac{2}{3}$
  1 mark · Use the simple interest formula
4. ✓
  Answer in years and months $\frac{2}{3}$ of a year $= \frac{2}{3} \times 12 = 8$ months
  It will take $6$ years and $8$ months to make R45 000 from R30 000 at a simple interest rate of $7, 5%$ p.a.
  1 mark · Convert units of measurement

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