Please help me?!:):!:):!? S sv

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?

1.based of the diagrams what is the the value of x? 2.how would you verify your answer for x

Which is the standard form for this number? (2 x 10) + (5 x 1) + (8 x 1 10,000 )