I think I understand what you are asking. Actually, from 13.75" you have enough for five 2 1/2 inch strips but you only need 4 - this is how I would cut it:
You can cut 3 - 10 1/2 inch pieces and 1 - 6 1/2 inch pieces on two of them (38" total)
Next one cut 2 - 10 1/2 inch pieces and 2 - 6 1/2 ' pieces (34" total)
Last one cut 6 - 6 1/2 inch pieces