Question 481337
Shelia and Todd drove a total of 503 miles in 12.8 hours.
 Todd drove the first part of the trip and averaged 45 miles per hour. 
Shelia drove the remainder of the trip and averaged 35 miles per hour.
 For what length of time did Todd drive?
:
Let t = length of time driven by Todd
then
(12.8-t) = length of time driven by Shelia
:
Write a distance equation; dist = speed * time
:
T's dist + S's dist = 503 mi
45t + 35(12.8-t) = 503
45d + 448 - 35t = 503
45d - 35t = 503 - 448
10t = 55
t = {{{55/10}}}
t = 5.5 hrs driven by Todd
:
:
Check solution by finding the total of the dist driven by each
12.8-5.5 = 7.3 hrs by Shelia
45(5.5) + 35(7.3) =
247.5 + 255.5 = 503 mi confirms our solution