Answer:
Molly's ribbon is 4 feet long!
Since Molly's ribbon is a fraction of Kelly's, we can multiply Kelly's ribbon length by 1/7.
28 x 1/7 = 4
So, the ribbon is 4 ft long
Or you could just divide 28 ft by 7, and you'd still get the same answer (note: this doesn't always work though, only when the numerator is a 1.)
I really hope this helps you out! Have a great day! :)