Solve the below:
1) If x varies directly as y, and x=20 when y=4, find x when y=6
2) Find the slope of the line that goes through the given points.
(-3,5) and (2,-10)
3)A parking garage charges $2.21 for the first hour and $0.50 for each additional hour or part of an hour. what is the maximum length of time Tom can park in the garage if he wishes to pay no more than $6.71
4) y varies directly as the aquare of R. if y=80 when R=4, find y when R=3