The new iPhone 3.14 is being sold at the UT Math Department. The original price is $900 (day 0), but they are going to decrease the price of the phone by x percent each day. You decided to wait until the price dropped to $100 on the 2nd day to purchase yours. Determine the equation that models the price of the iPhone 3.14 after t days.

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?