Suppose that c varies jointly with d and the square of g, and c = 30 when d = 15 and g = 2.
find d when c = 6 and g = 8. write the equation of the variation.

David and alton are training for a race. they spend 35 minutes stretching and then go on a 5 mile practice run. david runs at a pace of 7 min/mile. alton runs at a pace of 8 min/mile. write an equation for each runner that shows the total length of their workout. then solve each equation showing your work