Question 113457
volume of 2 pits =2xpixrxrxh=2x(22/7)x(12/2)x(12/2)x40= 9051.42 cu in	
volume of pole=2(LxBxH)=2x	770=1540 cu in			
volume of cement needed = vol of pits-vol of poles=9051-1540=8281.42cu inch
volume of cement needed = 8281.42cu inch/(12x12x12) cu ft = 4.34 cu ft
no of bags	= Vol of cement needed /one bag capacity= 4.34/0.6=7.2 
Say 8 bags ( the next integer)
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He has to buy 8 bags of cement 
okay