Calculate the total amount of interest Marcus would earn, in AUD, over the three years. Give your answer correct to two decimal places.

Marcus would earn the same amount of interest, compounded annually, for three years if he deposits the 500 AUD in a second bank.

Calculate the interest rate the second bank offers.

$500{\left( {1 + \frac{6}{{100 \times 4}}} \right)^{4 \times 3}} - 500$     (M1)(A1)

Note: Award (M1) for substitution in correct formula (A1) for correct substitutions.

$= 97.81$     (A1)     (C3)

Note: The answer must be given to 2 dp or the final (A1) is not awarded.

$97.8090... = 500{\left( {1 + \frac{r}{{100}}} \right)^3} - 500$     (M1)(A1)(ft)

Note: Award (M1) for substitution in correct formula, (A1)(ft) for their correct substitutions.

$= 6.14$ (6.13635...)     (A1)(ft)     (C3)

Note: Follow through from their answer to part (a).