An amount of R10 000 was invested in a special savings account on 15 May at an interest rate of 15% per annum, compounded quarterly for seven months. Interest is calculated on 1 January, 1 April, 1 July and 1 October of every year. (a) if the simple interest is used for the odd periods and the compound interest for the res of the term, the amount of interest received after 7 months is ? (b) if fractional compounding is used for the full term of seven months, the total amount of interest received is ?