What is the direct variation equation if y varies directly with x and y = -18 when x = 3?
1. Y = -1/6x
2. Y= -3x
3. Y= -6x
4. Y= -15x

Martha is training for a duathlon, which includes biking and running. she knows that yesterday she covered a total distance of over 55.5 miles in more than than 4.5 hours of training. martha runs at a speed of 6 mph and bikes at a rate of 15.5 mph.