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#1 2005-04-05 01:35:06
- austin81
- Member
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yet another problem
A cylindrical tunnel 5.5m in diameter is driven through a mountain for a distance of 7km. the ezcavated earth i s spread to a depth of 50cm on the surface of a road 11m wide. Calculate the number of ilometers of the road that can be covered with all of the excavated earth. (Take pi as 22/7)
#2 2005-04-05 07:50:39
- MathsIsFun
- Administrator
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Re: yet another problem
These are nice problems ... 
I think this one can be solved by just working out the volumes. Figure the volume of the cylinder, then divide it by (0.5 x 11).
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman
#4 2005-04-21 04:49:29
- mathsyperson
- Guest
Re: yet another problem
Total excavated earth: Pi*5.5m squared*7km=665500 cubic metres (Taking Pi as 22/7)
Length of road covered: 665500/(0.5m*11m)=121km.
Answer: 121km