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What is the anwers for 9+2x=5x-3-x

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?

An amusement park manager determined that about 23 of all customers would wait in long lines to ride the new roller coaster. which simulation could not be used to answer questions about whether a customer would wait?