Dave and his sister picked out two pumpkins at the pumpkin patch. the pumpkins cost $0.47 per pound. davids pumpkin weighed 13.24 pouns and his sisters weighed 10.6 pounds. how much did they pay for both pumpkins

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?