Please help with a explanation

Is the square root of 4 plus the square root of 16 rational?

Find the nonpermissible replacement for binthis expression.b2/5b +5

Mahnoor randomly selects times to walk into a local restaurant and observe the type of music being played she found that the restaurant was playing country 11 times rock & roll 17 times and blues 8 times use the observed frequencies to create a probability model for the type of music the restaurant is playing the next time mahnoor walks in.