Question 157259
d/36+d/48=(40-5)/60
(4d+3d)/144=35/60
7d*60=144*35
420d=5040
d=5040/420
d=12 miles for each trip.
Proof
12/36+12/48=35/60
1/3+1/4=7/12
(4+3)/12=7/12
7/12=7/12