3. Abeeha is standing with a tree directly between her and a building. She stands so that, in her eyes, the top of the tree appears to "touch" the top of the building. If the distance between her and the
tree is 30 ft, the distance between the tree and the building is 15 ft, and the tree is 20 ft tall, how tall
is the building? (You may ignore her height.)
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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?