Matt has been training for the Mount Pine Bike Race. The first week he trained, he rode 5 days and took the same two routes each day : 6 miles to work in the morning and a longer route home in the afternoon. By the end of the week, he had ridden a total of 70 miles. Which equation can you use to find how many miles, x, Matt rode each afternoon?
a 6x+5=70
b 6(x+5)=70
c 5(x+6)=70
d 5x+6=70