To calculate the total time Rosalie spends exercising in a week, you first need to determine how much time she exercises each day and then multiply that by the number of days in a week.
- Rosalie exercises for \( \frac{2}{5} \) of an hour every morning.
- In a week, there are 7 days.
Now, multiply the time she exercises each day by 7:
\[ \text{Total exercise time in a week} = 7 \times \frac{2}{5} \]
To perform the multiplication:
\[ 7 \times \frac{2}{5} = \frac{7 \times 2}{5} = \frac{14}{5} \]
Now, we need to convert \( \frac{14}{5} \) into a mixed number. To do this, divide the numerator (14) by the denominator (5):
- 14 divided by 5 is 2 with a remainder of 4.
So, we can express \( \frac{14}{5} \) as:
\[ 2 \frac{4}{5} \]
Therefore, Rosalie spends \( 2 \frac{4}{5} \) hours exercising in a week.