Atrain leaves little rock, arkansas, and travels north at 70 kilometers per hour. another train leaves at the same time and travels south at 55 kilometers per hour. how long will it take before they are 375 kilometers apart?

This is a two-part algebraic equation, meaning there are two consistent factors of different amounts. Since time (t I'll say) will always remain a constant factor, the equation will look like:     55(t) + 70(t) = 375

To find (t) or time, you will want to start by combining like terms, so that the equation is:     125(t) = 375

Dividing the equation by 125 so that (t) will be separated from all other factors
125(t) = 375
   ==> (t) = 3 hours
      125