Ok now that i understand the question better i say it is D
In order to answer this question let's suppose,
Joe is x miles from the beginning and y miles from the end. These assumptions are necessary to answer further:
Now,
x=2y
x+y=30
plugging in x=2y in the above equation
2y+y=30
3y=30
y=10
Hence, according to our calculations, Joe has to hike 10 miles further
Answer: B. 
Step-by-step explanation:
The formula to find the compound amount (compounded yearly):-
, where P is the principal amount invested, is the rate of interest and t is time period.
As per given , we have
P=$5500 , r=5% = 0.05 and A = $7,739.05.
Substitute all the values in the formula , we get


Hence, the equation describes Meredith's investment based on t, the number of years she kept the account open : 