math
posted by cas .
AT Mr. Hoopers Video rentals you can join a video club for a monthly fee of $30. Club members pay only .85$ to rent each movie. If you are not a member of the video club, the movies rent for $2.25 each. How many videos would you have to rent each month to make the membership worth the investment?

set the two costs equal
2.25n=30+.85n
solve for n.