You put $400 in an account earns $18 simple interest in 9 months.What is the annual interest rate?
I = PRT
18 = 400 * R * 0.75
18 = 300R
18/300 = R
0.06 = R
sorry its 6
To find the annual interest rate, we need to use the formula for simple interest:
Simple Interest = Principal × Rate × Time
Given the principal (P) is $400 and the simple interest (I) is $18. We also know that the time (T) is 9 months.
So, we can rearrange the formula to solve for the rate (R):
Rate = Simple Interest / (Principal × Time)
Plugging the values into the formula:
Rate = $18 / ($400 × 9/12)
= $18 / ($400 × 3/4)
= $18 / ($300)
= 0.06 or 6%
Therefore, the annual interest rate is 6%.