If I'm reading this right, we need 3/4 space allowed on each end that can't be used for stamping, and each stamping requires an area of 1 over 3/8 inches. How many will fit in a 72 inch strip?

I think this is how to solve it...

3/4+3/4+11/8(n) = 72

6/4+11/8(n) = 72

1.5+1.375(n) = 72

-1.5 -1.5 -Subtract 1.5 from both sides

1.375(n) = 70.5

/1.375 /1.375 -Divide both sides by 1.375

n = 51.272727

It asked for complete strips, so a total of 51 complete strips can be made out of this peice of aluminum.

Let's check it:

1.5+1.375(n) = 72

1.5+1.375(51.272727) = 72

71.999999999 ~= 72 ✔