The simple interest formula is , A = P + Prt, where
A = the full amount paid for the loan
P = the principle or the amount borrowed
r = the interest rate as a decimal
t = time in years
A car dealership wants to use the formula to find the rate needed for certain values of the other variables. Solve the formula for r.
r =
To solve the formula for r, we need to isolate r on one side of the equation.
The formula is A = P + Prt.
Subtract P from both sides:
A - P = Prt.
Divide both sides by Pt:
(A - P) / Pt = r.
Therefore, the formula for r is:
r = (A - P) / Pt.
To solve the formula for r, we can rearrange the formula as follows:
A = P + Prt
Subtracting P from both sides:
A - P = Prt
Dividing both sides by Pt:
(A - P) / Pt = r
So, the formula for r is:
r = (A - P) / Pt