What's the answer i don't know have to do it

Look at the given graph.  Start at x=0.  Mark x=1/8.  The first cut piece will have length 1/8, which stretches from x=0 to x=1/8.  Mark x=1/4.  The second cut piece will have length 1/8, which extends from x=1/8 to x=1/4.  And so on.  When you finally have a cut piece the ends at x=3/4, count the number of cut pieces that you have drawn between x=0 and x=3/4.