Tyler the poor sailor had 112 boats and crashed 50 of his boat while trying to take in his inhaler. While on the other hand his father only crashed 8 of his 22 boats he gave his left over to his son Tyler. Tyler crashed half of the boats his father gave him and got 11 more. How many does he have left? I will give you brainliest if you explain to me how you got the answer :)

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?