With this question(it’s attached)! urgent ! i will reward brainliest to the best/first answer. in advance!

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?

Tell whether the two rates form a proportion

What is the value of x? enter your answer in the box.