You can
put this solution on YOUR website!Jim wants to buy cement to anchor two posts for a swing he is building. He has dug 2 round holes that 12 inches in diameter and 40 inches deep. He wants to fill each with concrete around a rectangular supporting beam that is 3.5 inches by 5.5 inches. Each 80-pound bag of concrete mixes with water to make 0.6 cubic fee of concrete. How many bags of concrete must he buy for the job?
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Volume of the post: 3.5*5.5*40 = 770 cu. in.
Volume of the holes: 2*(pi)6^2*40 = 9047.786842 cu. in
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Volume he needs to fill with concrete:
9047.786842-770 = 8277.786842 cu. in
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1 cu. ft of of concrete = 12*12*12 = 1728 cu. in.
0.6 cu. ft. = 0.6*1728 = 1036.8 cu. in.
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# of bags = 8277.786842/1036.8 = 7.98 bags
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He needs to buy 8 bags.
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Cheers,
Stan H.
You can
put this solution on YOUR website!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
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