Two buses leave columbus, ohio at the same time and travel in opposite directions. one bus averages 55mi/h and the other averages 48mi/h. when will they be 618 mi apart?

Two buses going in opposite directions, one at 55mph, the other a 48mph. That means in 1 hr, the first bus would have traveled 55 mi and the second will have traveled 48 mi. 55+48=103mi apart. We can use this to set up our equation, with x being the number of miles traveled: 55x+48x=619 

55x+48x=619 
103x=619 
x=6 
6 miles is your answer.

It should be c i think.