I need some help with creating a formula that can calculate the price, depending on which week the purchase was made.

We’re selling weekly courses from February till July (23 weeks in total, €15,- each) The full program is €345,- When customers book a year in advance they get a €20 discount. I got up to the point where I made a formula that works and kinda goes like this:

**IF weeknumber < 5, the price is €345**

**IF weeknumber > 28 the price is €325**

Since people can join our courses at any giving time. I would like to add a formula that calculates the price depending on the week they joined. I’m looking for a formula that kinda goes like this:

**IF weeknumber is between 6 and 27, the price is €420 - (weeknumber x €15)**

Unfortunatly my coding isn’t that good yet… If anyone could help me out combining all of this in one formula, I’d feel blessed!