If each runner runs 1/3 mile, how many runners must be on a team?

Find the slope of a line given the following two points

Aschool puts on a play. the play costs $1,200 in expenses. the students charge $4.00 for tickets. there will be one performance of the play in an auditorium that seats 500 people. what is the domain of the function that shows the profit as a function of the number of tickets sold?  

Can you me find the missing length. i attached an image.