Assuming the interest rate is an anual one we find the interest by the formula:
where P is the principal, r is the interes rate and t is the time of the loan. (In this case we are dividing the result by 365 so we know the exact interes in 60 days).
Then:
Therefore the interest is $162.74.
To find the total amount that must be paid we add the interest to the principal:
Summing up:
a)
$162.74
b)
11162.74