Kunal borrows 200 000 Indian rupees (INR) from a money lender for 18 months at a nominal annual interest rate of $15\%$, compounded monthly.

Calculate the total amount that Kunal must repay at the end of the 18 months. Give your answer to the nearest rupee.

$A = 200000{\left( {1 + \frac{{15}}{{100 \times 12}}} \right)^{1.5 \times 12}}$     (M1)(A1)

Note: Award (M1) for substituted compound interest formula, (A1) for correct substitutions.

$= 250115.4788$ INR     (A1)

$= 250115$ INR     (A1)     (C4)

Note: Award final (A1) for their answer correct to the nearest rupee.

[4 marks]

In part (b), some candidates simply worked out the interest earned. If a correct substitution into the correct formula was seen leading to $50115$ then only one mark was lost. Whilst many correctly quoted formula were seen in part (b), an incorrect substitution (particularly poor or missing use of the factor $12$) lost the next two marks and, whilst the final mark could be earned irrespective of incorrect working, many candidates either ignored the final demand or did not know how to give their answer to the nearest rupee.