What is the shortest duration reguired to cimplete an activity

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?  

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

Find the area of the region that is inside r=3cos(theta) and outside r=2-cos(theta). sketch the curves.