This a Normal distribution problem. Problem: Let Z∼N(0,1). Find P(Z≤z) (3 decimal accuracy)

Find the solution of this system of equation -7x+y=-20 9x-3y=36

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?

What is 140% of 25? because i need