You can rent time on computers at the local copy center for a $6 setup charge and an additional $5.50 for every 10 minutes. how much time can be rented for $21?

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

The length of a rectangular piece of land is 92 yards more than three times its width. the perimeter is 760 yards. find its dimensions.

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?