For the last 4.5 hours, the temperature has decreased at a rate of 2.8 °F per hour. Which best represents the overall change in temperature over this time period? A -12.6 °F B -1.6 °F C 1.6 °F S 12.6 °F

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?