Zack needs to divide these base-ten blocks into 3 equal groups. Complete the description of the model to show how many are in each group. ten1 ten1 ten1 ten1 cube1 cube1 The model will contain tens rod(s) and ones cube(s).

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?