What is u=b+a-k solve for a

At the newest animated movie, for every 9 children, there are 4 adults. there are a total of 39 children and adults at the movie.

Sunday: 1 1 2 monday: 1 tuesday: 2 1 2 wednesday: 1 3 4 thursday: 2 friday: 1 1 2 saturday: 2 jenna is a swimmer and trains every day. the schedule shown outlines the number of hours she trains each day. what is the total number of hours that jenna trains during the week?

Pat listed all the numbers that have 15 as a multiple write the numbers in pats list