Dwayne opens a savings account. He makes the same deposit every month and makes no withdrawals. After 3 months, he has $150. After 6 months, he has $300. After 9 months, he has $450 dollars. What is the rate of change?​

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?