Answer:
19/24 pounds of grapes
Step-by-step explanation:
The LCD here is 24; both 8 and 12 divide evenly into 24.
Thus, the original problem involves adding:
9
-----
24
+ 10
------
24
and this sum comes to (9 + 10)/24, or 19/24.
She bought 19/24 pounds of grapes.
