Lydia wants to ride her bicycle 48 miles this week. She has already ridden 18 miles. If she rides for 6 more days, which tape diagram could be used to represent the context if x represents the average number of miles she would have to ride to meet her goal?
a) (18/x) + 6
b) 18 + (x/6)
c) 18 + 6x
d) (48 - 18)/6