6 1/2" squares should make a block that is 18" - finishes to 17 1/2". 2 yards of A will give you 60 squares - might squeeze out 66 if you cut perfectly and the fabric doesn't shrink. 60 sq will do 15 blocks, but that's not a good number to work with. If you do 12 - 3 across X 4 down- the proportions will be better. 52 1/2 X 70 before any borders. You can increase the size by adding sashing between the blocks, too. You only need a half yard of C unless you are repeating it in your stopper strip before the borders or the binding.
What size quilt is your friend thinking of?
Last edited by irishrose; 03-07-2013 at 08:36 AM.