What formula represents simple interest?

The formula that represents simple interest is I = prt, where I stands for the interest earned, p is the principal amount (the initial amount of money), r is the rate of interest (expressed as a decimal), and t is the time the money is invested or borrowed for, typically expressed in years.

This formula is straightforward because it directly calculates the interest earned over a specified period based on a constant principal, interest rate, and time frame. The relationship is linear, meaning that the interest earned grows proportionally with time and does not take into account the compounding of interest.

The other options presented involve different calculations or concepts. For instance, one option reflects the formula for compound interest, where the amount of interest earned changes based on prior interest accumulation. Another describes the total amount as the sum of the principal and interest earned, which doesn't directly represent simple interest itself. Thus, I = prt clearly captures the definition and calculation of simple interest.