Hello!
To find the rate, you'll need to follow this formula
I=P*r*t
30=250*r*3
First, you'll need to rearrange the equation
30=250*3*r
Now you'll need to multiply 250 by 3 to get 750.
30=750r
Now you'll need to divide both sides by 750. Once you've divided 30 by 750 (30/750) you'll get 0.04. Next, you'll move the decimal twice to the right to get 4 or 4% as your rate.
Your rate is 4%
I hope this helps!