Final answer:
To find the interest rate given the simple interest, time period, and principal, rearrange the formula I = PRT to solve for R. With an interest of $700, a principal of $200, and a time period of 7 years, the interest rate is calculated as 50%. The interest rate is 50%.
Step-by-step explanation:
To calculate the interest rate for simple interest when the principal, interest, and time period are known, you can use the formula I = PRT, where I is the interest, P is the principal, R is the rate, and T is the time in years. In this case, we know that the interest (I) is $700, the principal (P) is $200, and the time period (T) is 7 years. We are solving for the rate (R).
Rearranging the formula to solve for R, we get R = I / (PT). Plugging in the values, we have R = $700 / ($200 × 7). Therefore, R = $700 / $1400, which simplifies to R = 0.5 or 50%.
The interest rate is 50%.