Hamish borrowed $5000 for 3 years. He paid $1650 simple interest. What was the rate of interest per annum?
r = I/pt *100
r = 1650/(5000*3)
r = .11 or 11%
To find the rate of interest per annum, we can use the formula for simple interest:
Simple Interest (SI) = Principal (P) x Rate of Interest (R) x Time (T)
In this case, the principal borrowed (P) is $5000 and the time (T) is 3 years. We are given that the simple interest paid (SI) is $1650. By rearranging the formula, we can solve for the rate of interest (R):
R = SI / (P x T)
Substituting the values into the formula:
R = $1650 / ($5000 x 3)
R = $1650 / $15000
R ≈ 0.11
Therefore, the rate of interest per annum is approximately 0.11 or 11%.