Answer:
The correct option is;
A total of forty hours a week
Step-by-step explanation:
The given information in the question are;
The number of hours of sleep Nina gets during weeknights = five hours
The number of hours of sleep Nina gets per night on weekends = ten hours
The number of days in a week = 5 days
The number of days in a weekend = 2 days
Therefore;
The number of hours of sleep Nina gets per week = 5 days × 5 hours/day + 2 days × 10 hours/day
∴ The number of hours of sleep Nina gets per week = 25 hours + 20 hours = 45 hours
The number of hours of sleep Nina gets per week = 45 hours
To better concentrate on schoolwork, Nina could get a total of forty hours a week of sleep a week to increase the number of hours she spends weekly on her schoolwork by up to 5 hours (45 hours - 40 hours).
