All solutions here are SUGGESTED. Mr. Teng will hold no liability for any errors. Comments are entirely personal opinions.

(i)

Using the graphing calculator, smallest n = 24.

Thus, Mrs A’s account will have more than 5000 dollars on 1 December 2002.

(ii)

Amount at the end of 1st month

Amount at the end of 2nd month

Amount at the end of nth month

Mr B’s account will be more than 5000 dollars on September 2004.

(iii)

Using Graphing Calculator,

Thus the interest rate is 1.80% per month.

### KS Comments:

Students should reproduce the table (with its succeeding and preceding values) to substantiate their answers for (i) and (ii). For (i), its necessary to identify the month; just use your fingers to count.