A car that normally sells for $20,000 is on sale for $16,000. The sales tax is 7.5% What percent of the original price of the car is the final price? Show your work to solve this problem.

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?