Rectangle ABCD has side lengths of 6 centimeters and 8 centimeters. Rectangle EFGH has side lengths of 9 centimeters and 12 centimeters. Determine the ratio of corresponding side lengths if ABCD is similar to EFGH. 1:3
2:3
3:1
3:2

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?