Need help with a formula

Question

Let's say Bob's Farmers Market sells carrots. Bob also tries to cross-sell carrot peelers.

My know variables are:

Bob sold a total of 60 units (including carrots + peelers)

Bob was able to cross sell peelers with his carrots 50% of the time

How would I calculate how many carrots were sold?

Answer 1

I can calculate it in head with basic logic. There would be 40 carrots and 20 peelers. I can't figure out how I would calculate a more complex scenario.