Atrain leaves little? rock, arkansas, and travels north at 90 kilometers per hour. another train leaves at the same time and travels south at 80 kilometers per hour. how long will it take before they are 680 kilometers? apart?
Ahousekeeper mixed 5 gallons of blue paint with every 9 gallon of yellow paint in order to make a green paint which ratio of gallon of blue paint to gallon of yellow paint will make the same shade of green paint