Excel Formula Help - Add specific value based on cell value

Hello all,

Would appreciate some help with building a formula. I've provided a more basic example of what I need below.

I want to complete Column C, by adding a certain value to Column B, depending on the content of Column A.

If A1 = Up, I want C1 to be 1000+50

If A1 = Down, I want C1 to 1000+100

For reasons not worth going into, I don't want to use a formula which references back to a cell containing either "50" or "100". I want to build a formula which includes the "50" or "100" values in the formula itself.

But this is beyond my expertise, and I've not been able to make it work. I would appreciate any help.