I = Prt Always remember this. It si the essence fo Simple Interest.
We have P = 5000
I = (5000)rt
We ahve r = 0.085
I = (5000)(0.085)t
We have t = 120 days. This is a little bit of a problem. Different things use different numbers of days for a total year. Let;s just use 365 days for a full year.
I = (5000)(0.085)(120/365)