A sparse ruler is called optimal if it is both minimal and maximal. Since the number of distinct pairs of marks is m ( m â 1 ) / 2 {\displaystyle m(m-1)/2} , this is an upper bound on the length L {\displaystyle L} of any maximal sparse ruler with m {\displaystyle m} marks.
1 One 23/32-inch 4x8-foot plywood piece weighs approximately 67 pounds, while a piece of OSB of the same dimensions weighs approximately 78 pounds.
The Yahoo search function works wonders... An easy way to estimate how much a stack of plywood will weigh is to figure about 25 lbs. per 1/4 in. of thickness. For example, one 4x8-ft. sheet of 1/4-in. plywood will weigh about 25 lbs., 1/2-in. about 50 lbs., and 3/4-in. about 75 lbs. This can help you decide how many trips you need to make to get a stack home, or whether you should have it delivered.