Mr. Huáng bought 2 bottles of maple syrup for his grandchildren to share equally at breakfast
tomorrow. If each grandchild uses bottle of
syrup on his or her pancakes, and all of the syrup
in the bottles is used, how many grandchildren
must Mr. Huáng have?
A 8 B 12 C 6 D 18

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?