Obi travels from Dubai to Pretoria and changes \(2000\) United Arab Emirates Dirham \(({\text{AED}})\) at a bank. He receives \(6160\) South African Rand \(({\text{ZAR}})\).

The exchange rate is \(1\;{\text{AED}} = x\,{\text{ZAR}}\).

Calculate the value of \(x\) .

Obi decides to invest half of the money he receives, \(3080\,\,{\text{ZAR}}\), in an account which pays a nominal interest rate of \(9\,\% \), compounded monthly.

The amount of money in the account will have doubled before the end of the \(n{\text{th}}\) year of the investment.

Calculate the minimum value of \(n\) .

\(\frac{{6160}}{{2000}}\)       (M1)

\( = 3.08\)       (A1)    (C2)

Note: Award (M1) for correct division.

\(3080\,{\left( {1 + \frac{9}{{12 \times 100}}} \right)^{n \times 12}} = 6160\)          (M1)(A1)

Note: Award (M1) for substitution into compound interest formula equated to \(6160\), (A1) for correct substitution.

OR

\(I = 9\)

\(PV =  \pm 3080\)

\(FV =  \mp 6160\)

\(P/Y = 1\)

\(C/Y = 12\)          (A1)(M1)

Note: Award (A1) for \(C/Y = 12\) seen, (M1) for other correct entries.
\(FV\) and \(PV\) must have opposite sign.

\( = 7.73048...\)          (A1)

\( = 8\)          (A1)(ft)       (C4)

Note: Award the final (A1)(ft) for the correct rounding up, of their unrounded answer, to complete years.

Question 10: Currency conversion and compound interest.

Currency conversion was done well by all but the weakest candidates. Most of the candidates that used the compound interest formula did a correct substitution but some did not equate this to the future value and found solving an equation to be challenging. Candidates that used the financial application on their GDC almost always wrote down a correct unrounded answer.

Question 10: Currency conversion and compound interest.

Currency conversion was done well by all but the weakest candidates. Most of the candidates that used the compound interest formula did a correct substitution but some did not equate this to the future value and found solving an equation to be challenging. Candidates that used the financial application on their GDC almost always wrote down a correct unrounded answer.