Step 1 :Given the principal amount (P) is $6000, the rate of interest (r) is 7.5% per annum, and the time period (t) is 9 months.
Step 2 :First, we need to convert the rate of interest into a fraction and the time into years. So, r = 7.5/100 = 0.075 and t = 9/12 = 0.75.
Step 3 :Then, we substitute these values into the formula for simple interest, which is I = P*r*t.
Step 4 :Substituting the values, we get I = 6000 * 0.075 * 0.75 = 337.5.
Step 5 :\(\boxed{337.50}\) is the simple interest owed for the use of the money.