For this case we must add the fractions:
Milk for breakfast: [tex]\frac {3} {8}[/tex]
Milk for dinner:[tex]\frac {4} {5}[/tex]
So, we have:
[tex]\frac {3} {8} + \frac {4} {5} = \frac {3 * 5 + 8 * 4} {5 * 8} = \frac {15 + 32} {40} = \frac {47 } {40}[/tex]
Thus, Dan drank[tex]\frac {47} {40}[/tex] of milk in total.
Answer:
Dam drank [tex]\frac {47} {40}[/tex] of milk in total.