First, find how much time is spent in classes. We do this by subtracting 1/2 and 7/10 from 7 3/5.
We can do this by putting all of the fractions over 10. This becomes:
[tex] 7\frac{6}{10} -( \frac{5}{10} + \frac{7}{10})=6 \frac{4}{10} =6 \frac{2}{5} [/tex]
Now, we divide 6 2/5 by 6 to see how long she is in each class individually. This is equal to 1 1/15, so she is in each class for 1 1/15 hours, or A.
