Answer: the total amount of time
it takes to shower and eat breakfast is 2/3 hour.
Explanation:
The total amount of time that it takes Marty to get ready for school is 1 1/4 hours. Converting to improper fraction, it becomes 5/4 hours.
If 1/5 of that time is used to shower, it means that the it takes to shower is 1/5 × 5/4 = 1/4 hour.
If 1/3 of that time is used to eat breakfast, it means that the time it took to eat breakfast is 1/4 × 5/4 = 5/12 hour.
Therefore, the total amount of time
it takes to shower and eat breakfast is
1/4 + 5/12 = 8/12 = 2/3 hour