Question 196209
Cabrina and Dabney are attending a conference. After the conference, Cabrina
 drives home to Boise at an average speed of 75 mph and Dabney drives home to
 Portland at an average speed of 60 mph. If the sum of their driving time is
 11.3 hours and the sum of distance driven is 783 miles, 
determine the time each woman spent driving home.
:
Let t = C's driving time
It states the sum of their times is 11.3, therefore:
(11.3 - t) = D's driving time
;
:
The sum of their distances is given as 783 mi, write distance equation:
Dist = speed * time
:
C's dist + D's dist = 783 mi
75t + 60(11.3 - t) = 783
:
75t + 678 - 60t = 783
:
75t - 60t = 783 - 678
:
15t = 105
t= {{{105/15}}}
t = 7 hrs is C's driving time
and
11.3 - 7 = 4.3 hrs is D's driving time
:
:
Check solutions by finding the sum of the distances
75(7) + 60(4.3) = 
525 + 258 = 783, confirms our solutions