4x+7=43 solving two-step equations

The number of hours per week that the television is turned on is determined for each family in a sample. the mean of the data is 37 hours and the median is 33.2 hours. twenty-four of the families in the sample turned on the television for 22 hours or less for the week. the 13th percentile of the data is 22 hours. approximately how many families are in the sample? round your answer to the nearest integer.

The graph shown is the graph of which function?

I'm confused on this could anyone me and show me what i need to do to solve it.