Ajar contained 18 red marbles, 14 green marbles, and 20 blue marbles. a marble was selected at random, the color was recorded, and the marble was placed back in the jar. the table shows the results after 60 trials.
outcome
number of times outcome occurred
red 22
green 18
blue 20

what was the relative frequency of selecting a blue marble?

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?