For this case we have the following equation:

The variables are:
t: time in hours
d (t): distance traveled in miles.
We evaluate the distance traveled after 4 hours.
So we have that for t = 4:
Answer:
d (4) = 68
This means that after 4 hours Joanna cycled for 68 miles total
Answer:
The answer should be 14/15.
Step-by-step explanation:
The answer is 14/15 because -2/5 and 4/3 with a common denominator turns into -6/15 and 20/15.
Then you add both of them together.
-6/15 + 20/15 = 14/15
I think the answer would be 155.61