Question 992159
.
let x be the speed of the westbound train in mph.


The the speed of the other train is x-12 mph.


The distance between the trains increases by [x + (x-12)] = 2x-12 miles each hour.


The equation to find x is 


{{{800/(2x-12)}}} = {{{5}}}.


Simplify and solve it:


800 = 5*(2x-12),


800 = 10 x - 60,


10x = 860,


x = {{{860/10}}} = 86 mph.


<U>Answer</U>. the speed of the westbound train is 86 mph.