Select all the correct answers. richard is renting a bike. the cost of renting a bike for the first hour is $7. he is charged $2.50 for every additional hour of renting the bike. select all the functions that can be used to find the total amount that richard is charged, f(n), for renting the bike for n hours.

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

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.

47: 4 aisha changed 1.45 + 2.38 to 1.5 + 2.4 in order to estimate the sum. what estimation method did she use?