Help with these, I will give brainiest!
They are due tonight help please...

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?

Hundred and tens tables to make 430 in five different ways

Which of the following segments is a diameter of o?