A popular Lemonade Mix requires cups of 2 1water(w) and cups of concentrated 3/1 juice(p)for one serving. However, I decided to not follow directions. I decided to put in 10 parts water and 20 parts concentrated juice. How many cups of this modified Lemonade would I end up with?

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?