Which expression gives the surface area of a sphere with radius r? A 4ttr ^2
B 4ttr^3
C 4/3ttr^2
D 4/3ttr^3

Find the solution of this system of equation -7x+y=-20 9x-3y=36

Every weekday, mr. jones bikes from his home to his job. sometimes he rides along two roads, the long route that is shown by the solid lines. other times, he takes the shortcut shown by the dashed line. how many fewer kilometers does mr. jones bike when he takes the shortcut instead of the long route?

The box plots show the data distributions for the number of customers who used a coupon each hour for two days of a store sale. what is the difference of the medians?