Ex. 1. If cement costs $1.35 a bbl., sand $0.75 a cu. yd., and crushed 

 stone $1.25 a cu. yd., what will be the cost of materials in a 1, 2, 3 mixture for 

 50 cu. yd. of concrete? 



Conclusion: The method of mixing and the proportion 

 of each material used. 



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