Final answer:
The effective interest rate can be calculated using the quarter-end payments, the number of payments, and the total loan amount, which typically involves setting up an amortization schedule or using a financial calculator.
Step-by-step explanation:
The question asks to determine the effective interest rate charged on a loan when the loan terms include quarter-end payments of $1,550 over 9 years to settle a loan of $40,300. The effective interest rate can be found by setting up an amortization schedule or using a financial calculator to solve the rate given the payment amount, number of payments, and loan amount.
A precise explanation would provide the formula for calculating the effective interest rate and even a step-by-step calculation using the given values. However, without additional context or specific formulae, a direct calculation is not feasible in this response.