Answer:
4.074 hours
Step-by-step explanation:
r =
The formula for speed = Distance × Time
Hence,
Let the outbound speed = r
return trip speed = r + 25x/100 = 125r/100 = 1.25r
Note that: 9 hours and 20 minutes = 9.167
Let t1 and t2 be the time taken to travel on way and return journey.
t1 + t2 = 9 hr 10 min = 9.167 hrs
Hence:
2688/r + 2688/1.25r = 9.167
LCM(1.25r)
(2688 × 1.25) + 2688 /1.25r= 9.167
3360 + 2688 = 9.167 × 1.25r
6048 = 11.45875r
r = 6048/11.45875
Outbound trip rl = 527.8062615904876mph
Return trip speed = r + 25x/100 = 125r/100 = 1.25r
= 1.25 ×
659.75782699mph
Time for return trip = Distance/Speed
= 2,688 miles/659.75782699mph/
= 4.0742222222 hours
Approximately = 4.074 hours
