Which pair of angles are alternate exterior angles ?

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?

Aphrase is shown read the phrase and give me the answer

Given sin28.4=.4756, cos28.4=.8796, and tan28.4=.5407 find the cos of 61.6