You and your mom enter a drawing with 3 different prizes. a total of 10 people entered the drawing, in how many ways can you win the first prize and your mom win the second?
a. 2
b. 8
c. 10
d. 1

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?