Tenesha bikes 8 miles each day, so she is going to need X days to complete the challenge. X can be calculated as:
Then, she goes to school 5 days every week and there is a day in which she can't bike, so she bikes just 4 days per week.
Therefore, the number of weeks Y that Tenesha needs to complete the challenge can be calculated using a rule of three as:
4 days ------------- 1 week
12.5 days ---------- Y
Solving for Y, we get:
Answer: she needs 3.125 weeks to complete the challenge