Thomas paid $50 for a box of multicolor file folder for his office there were 100 folders in the box what was the cost of each file folder

Two sides of a triangle mesure 20cm and 30cm. what is the measure of the third side

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?

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?