on a snowy day the amount of money Billy earns M varies directly with the number of driveways that he shovels D when he shovels 7 driveways he earns $80.50 how much dose he earn if he shovels 13 driveways

the amount a spring will stretch S varies directly with the weight F attached to the spring if a spring stretches 2.22 inches with 37 pounds attached how far will stretch when 25 pounds are attached.