Help with formula: IF, variable, add time into a different cell

Hello, I found this website after bumping my head with the keyboard trying to find a solution to a question I have.
I am trying to create a spreadsheet that will allow me to add a fix amount of time to a starting time. The whole process is to determine that if given a start time of day, and a duration of a process, what would be the end time of it.

This is what I could create so far, but I don't know how to add several variables on one formula. I was able to do it per variable on separate cells, but I'd like the formula to be on one cell altogether;

A1 is the original time, B1 will be a type of 3 equipment to choose from, C1 will be either 40, 45 or 55 minutes depending on type, depending on type of equipment on B1, then D1 will add C1 and A1 and throw a sum result of those to give me the end time.
I tried =IF(B1="319",+"0:40")*IF(B1="320",+"0:45")*IF(B1="321",+"0:55") And then D1=A1+C1 but all I get is zeros and no addition is made.

Any help pointing me on the right direction would be highly appreciate it.


Thanks!