Given values:
Principal = P = 6000 dollars
rate = r = 11% = 11/100 = 0.11 (use the decimal form)
time = t = 2 & 1/2 years = 2+(1/2) = 2+0.5 = 2.5 years
In short we have
P = 6000
r = 0.11
t = 2.5
We'll use these three values to find the simple interest 'i'
i = P*r*t
i = 6000*0.11*2.5
i = 1650
So the final answer is 1650