Val and Glen have each pledged a certain number of hours to volunteer for their community. The graph shown compares the numbers of volunteer hours remaining for Val and Glen over time, in weeks.
Volunteer Hours
у
25
20
Val
Hours Remaining
15
10 Glen
5
0
1 2 3 4 5
Time (weeks)

Best answer that i found on yahoo ok   set :   x= length of 2nd piece in cm  x- 3= length of 1st piece in cm  x-4= length of 3rd piece in cm  then since you know they all came from the 20 cm ribbon you add them together and set them equal to 20x+ x-3 +x-4 = 20  3x - 7= 20  3x= 27  x= 9  the shortest piece is the third piece which is x- 4  x-4  9-4 = 5  the length of the smallest piece is 5 cm.  the other lengths are  9 cm  6 cm

Sis less than or equal to 75 (bottom left)