how do you calculate quarterly compound interest?
['Calculate Accrued Amount (Principal + Interest) A = P(1 + r/n)nt', 'Calculate Principal Amount, solve for P. P = A / (1 + r/n)nt', 'Calculate rate of interest in decimal, solve for r. r = n[(A/P)1/nt - 1]', 'Calculate rate of interest in percent. R = r * 100.', 'Calculate time, solve for t.']