Herb is supposed to pay $1500 to Ranjit on September 20th. Herb wishes to delay payment until December 1st. What amount should Herb expect to pay on December 1st if Ranjit can earn 2.25% simple interest on a low-risk investment?

I will leave it up to you to count from Sept 20th to Dec 1st, suppose that

number is n
so you would pay back: (once you know n)
1500 + 1500(n/365)(.0225)
= ....