Grades 6, 7 and 8 - Math - Middle School - Business Math - Calculating Interest Per Day — Flashcards

You want to borrow some money for a short period of time, say $6,300.00 at 8% for 310 days.

We still use the formula I = PRT but now our worked problem should look as follows:

Example: $6,300.00 at 8% for 310 days
(as there are 365 days in a year but you are only using the money for 310 days, you show this in a fraction, i.e., 310 days/365 days)
300 x 0.08 x 310/365
300 x 0.08 = 504
$504.00 per year (but we don’t need the whole year so we must now divide as follows)
÷ 365 (days) = 1.3808219  (this means the interest per day [also referred to as per diem] is $1.3808219)
$1.3808219 x 310 (days) = $428.05
I = $428.05