Question

a train leaves little rock, arkansas and travels north at 70 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 at 450 kilometers apart

Answer 1

45 hours.
80 - 70= 10, and 450/10 is 45.
to justify, you can do 70x45= 3,150, and 80x45= (3,600 - 3,150= 450)