Answer:
If your patio is L feet long and W feet wide, you need 24L/11.8 rounded to the nearest greater integer plus 2*(12W-8.6)/11.8 rounded to the nearest greater integer curbs and (12W-8.6)(12L-8.6)/60.06 rounded to the nearest greater integer pavers.
Explanation:
Suppose your patio is L feet long and W feet wide.
Recall that 1 feet = 12 inches, 1 squared feet = 144 squared inches
Step 1
Multiply L and W by 12, to get the length and width in inches.
Example: if your patio is 18 feet long and 12 feet wide, it would be 216 inches long and 144 inches wide.
Step 2
Compute the number of curbs needed to enclose the patio.
For the length we need 12L/11.8 rounded to the nearest greater integer on each side
Example: As your patio 216 inches long, you would need 216/11.8 = 19 curbs on each side, that is, 38 curbs.
Now, the width of the patio has been reduced 4.3+4.3=8.6 inches.
So you need (12W-8.6)/11.8 rounded to the nearest greater integer on each side.
Example: As your patio is now 144-8.6 = 135.4 inches wide, you need 135.4/11.8 = 12 curbs on each side. That is, 24 curbs
Add the two figures obtained to compute the number of curbs.
Example: You need 38+24 curbs to enclose your patio.
Step 3
Compute the area of the patio after being enclosed
New width 12W-8.6, new length 12L-8.6
Multiply the numbers to obtain the area in squared inches.
Area: (12W-8.6)(12L-8.6)
Example: Your patio now has a new area (216-8.6)(144-8.6)=28,081.96 squared inches.
Step 4
Compute the number of pavers required.
As each paver is 7.75*7.75=60.06 squared inches, you need
(12W-8.6)(12L-8.6)/60.06 rounded to the nearest greater integer pavers.
Example: The number of pavers needed for your patio is
28,081.96/60.06 = 468 paver stones.