Question

In the formula I=P·r·t, what does r stand for?
a.
Rate: the percent that interest is paid annually as a decimal
b.
Ratio: the size of the interest interval compared to time
c.
Return: how much money you end up earning
d.
Reserves: how much money you have in the investment

Answer 1

a. Rate: the percent that interest is paid annually as a decimal.

(Example: 5% per year means r = 0.05; note t is time in years unless a different time unit is specified.)