Hint
Use the stated units and precision. Divide the final price by \(\displaystyle 1+ \frac{r}{100}\).
Worked solution
(a)
Divide the final price by \(\displaystyle 1+ \frac{r}{100}\).
\(600\)
Answer: \(600\)
(b)
Divide by \(\displaystyle 1- \frac{r}{100}\).
\(600\)
Answer: \(600\)
(c)
Multiply by both successive multipliers.
\(\displaystyle \frac{14904}{25}\)
Answer: \(\displaystyle \frac{14904}{25}\)
Maths4U indicative marking guidance
Maths4U indicative marking guidance, not an official mark scheme. Credit complete valid alternative methods and consequential reasoning. An unexplained result does not earn a method mark.
(a) · 2 marks
- 1 mark: Divide the final price by \(\displaystyle 1+ \frac{r}{100}\).
- 1 mark: Give the correct requested result, retaining signs, units and any domain restrictions.
Alternative methods: Any complete mathematically valid alternative method with the same restrictions and equivalent exact result is acceptable.
Common error: Keep intermediate values exact until the final step.
(b) · 2 marks
- 1 mark: Divide by \(\displaystyle 1- \frac{r}{100}\).
- 1 mark: Give the correct requested result, retaining signs, units and any domain restrictions.
Alternative methods: Any complete mathematically valid alternative method with the same restrictions and equivalent exact result is acceptable.
Common error: Check the answer against the original conditions.
(c) · 2 marks
- 1 mark: Multiply by both successive multipliers.
- 1 mark: Give the correct requested result, retaining signs, units and any domain restrictions.
Alternative methods: Any complete mathematically valid alternative method with the same restrictions and equivalent exact result is acceptable.
Common error: Keep intermediate values exact until the final step.
Total: 6 marks.