I need a explanation on how to find x.​

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?

Using only odd number for numerators write two different subtraction problems that have a difference of 3/4

Asoftball team played ten games, scoring 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 runs. they lost by one run in exactly five games. in each of their other games, they scored twice as many runs as their opponent. how many total runs did their opponents score?