236 FARM ARITHMETIC. 



rel, sand at $1.50 per cubic yard, and gravel $1.00 per 

 cubic yard? 



866. What would be the cost of the materials used in 

 the sidewalk in problem 854, if cinders are free for the 

 hauling, other costs are as in 865, a 1-2^-5 concrete is 

 used, and the surfacing is omitted? 



867. The materials used in the silo in problem 861 

 were, "one part best Portland cement, two parts clean 

 coarse sand, three parts clean fine gravel, and four parts 

 clean broken stone, brick or terra cotta." Assuming that 

 this was approximately a 1-3-6 concrete, determine the 

 quantity of cement used. 



868. If the surface finish in problem 854 be a 1-2-0 

 mixture and the volume after adding the cement to the 

 sand be the same as that of the sand, what is the amount 

 of cement required for the finishing coat? 



