Remark
You know the most about the trip on the way back and the total of the two trips.
Way Back
r = 30 mph
d = distance traveled
t = t - 1 where t = the time to go there which we know nothing about
Total Distance
2d = 25 mph * (t + t - 1)
2d = 25 * (2t - 1)
2d = 50t - 25 Divide by 2
2d = 50t/2 - 25/2
d = 25t - 12.5
Equation coming back
d = 30*(t - 1)
d = 30t - 30
Comment
Since the distances are the same, equate them.
Solution
25t - 12.5 = 30t - 30 Subtract 25t from both sides
25t - 25t -12.5 = 30t - 25t - 30 Combine like terms
-12.5 = 5t - 30 Add 30 to both sides
-12.5 + 30 = 5t - 30 + 30 Combine
17.5 = 5t Divide by 5
17.5/5 = t Divide and Switch
t = 3.5
t is the time going there
t - 1 is the time coming back
Total time = 2*t - 1 = 2*3.5 - 1 = 6
The total time is 6 hours. Answer
