Principal P = $2700
Time is 7.5 years
compounding interval is 0.5
interest per annum is 9/100
for half year, interest is 0.5 x 0.09 = 0.045
number of compoundings in 7.5 years is 7.5 / 0.5 = 15
Amount is given by
P = A (1+(r/100))^n
=2700 x (1+0.045)^15
=2700 x1.93528
=$5225.2626
Amount is $5225.2626
Principal is $2700
Interest I is 5225.2626-2700=$2525.2626