While swimming a 2 km race, adam changes from breathstroke to butterfly every 200 m. how many times does he switch trokes during the first half of the race

Which expression is equivalent to 4 square root 6 divided by 3 root 2

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

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?