Time for entire trip = 2d/30 hours
Time for first part of trip = d/60.
Time for second part of trip, is given by:

Therefore the speed during the second distance d is 20 mi/h.
Answer:
yes :)
Step-by-step explanation:
$1296
- 470 (parts)
= $826 labor
826/60 = approx. 13. hours