Final answer:
Beth has 2/15 of an hour left to exercise after subtracting the fraction of time she has already exercised (2/3) from the total time she wants to exercise (4/5).
Step-by-step explanation:
Beth wants to exercise for 4/5 of an hour and has already exercised for 2/3 of an hour. To find out how much more time she needs to exercise, we subtract the time she has already exercised from the total time she intends to exercise:
- Convert both fractions to have a common denominator, which is 15 in this case.
- 4/5 becomes 12/15 (since 4 × 3 = 12) and 2/3 becomes 10/15 (since 2 × 5 = 10).
- Subtract the time exercised from the total time needed: 12/15 - 10/15 = 2/15.
Therefore, Beth has 2/15 of an hour left to exercise.