You can solve this problem by applying the Simple interest formula, which is:
I=PxRxT
I: Simple Interest.
P: Principal.
R: Rate
T: Time (It must be expressed in years or a fraction of years).
You have:
P=$2500
R=9%=0.09
T=180 days=180/365
When you substitute these values into the formula, you obtain:
I=PxRxT
I=($2500)(0.09)(180/365)
I=$110.959
