Elena rolls two cubes numbered 1 to 6. What is
the probability that she rolls
two numbers with a sum of
9?

When a rectangle is dilated, how do the perimeter and area of the rectangle change?

41/17 as a decimal rounded to the nearest hundredth

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?