let us use a real life situation for example.
imagine a tasty pizza in front of you. your parents decide to cut half for themselves, so you're left with 1/2 of the pizza.
now imagine you have 7 siblings, and you want to share the pizza with everyone. hence, to find how much pizza the siblings get, you take
which equals to 7/16, as your siblings took 7/16 of the entire pizza.
you want the sum of the distances to equal 1900 miles.
they are travelling in opposite directions and therefore the distances will add.
let the number of hours = t
d = r*t
635*t + 325*t = 1900 combine the right
960*t = 1900 divide by 960
960t/960 = 1900/960
t = 1.98 hours or 1 hour and 58.8 minutes or 1 hour 58 minutes 48 seconds.
without choices, i don't know which answer you want. perhaps even 2 hours is (rounded) close enough