A diesel train traveled to New York and back. The trip there took 12 hours and the
trip back took nine hours. It averaged 10
km/h faster on the return trip than on the
outbound trip. Find the diesel train's
average speed on the outbound trip.

The path traveled by a bottlenose dolphin as it jumps out of water is modeled by the equation y=-0.4+3x, where t is the height above water and x is the horizontal distance in feet. if a beam of light is shone upward at an angle modeled by the equation x+y=10, at what height from the waters surface will the beam of light hit the dolphin