I need help ASAP ! Angles of triangles

What is the result of converting 60 ounces to pounds remember there are 16 ounces in a pound

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

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?