Answer:
Dana read stories for 3/4 hours, or 40 minutes
Explanation:
Before answering, its important to remember that 2/4 is equivalent to 1/2.
All you have to do is add 1/2 to 1 3/4. But for our sake lets convert 1/2 to 2/4. This leaves us with the following problem:
1 3/4 + 2/4 or 1 (3 + 2)/4 = 1 5/4
This resulting numerator is over the amount of our denominator, so we'll count that as one, resulting in the now simplified:
2 1/4
Now that we've calculated how long the children played and watched tv, simply subtract that from the 3 hours Dana spent babysitting.
3 - 2 1/4 = 3/4 hours
I'm not sure what unit they want the answer in, but I've included the solution in hours and converted to minutes as well.