Shelly took out a payday loan for $750 due in 4 weeks that charged a $90 fee. What is the periodic interest rate of the loan?

If the interest is $90 from $750 loan amount, we can calculate the periodic (4 weeks) interest rate of the loan using the below formula.

*interest amount / loan amount x 100 = periodic interest rate of loan*

To integrate the values, we have:

$90 / $750 = 0.12 multiplied to 100 will result to 12.

Therefore, the periodic interest rate of loan is 12% or $90 is 12% from loan amount of $750.