Hi there!
Let's first multiply 3/4 by 2 so that we can get it to have the same denominator as 1/8. Remember, whatever you do to the bottom, you must do to the top.
3/4 * 2/2 = 6/8
So, Johnathan has 3/4, or 6/8, pound of grapes.
Now, we just divide 6/8 by 1/8, which gives us 6.
Remember that when dividing fractions, you multiply the first fraction by the inverse of the second. In this case, we get 6/8 * 8/1. You cross-cancel the 8's and get 6/1 * 1/1, which gives you 6. (Just in case you needed help dividing fractions!)
Johnathan can make six 1/8 pound servings from his grapes.
hope that helped!