How to do this question?

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2 Answers
May 18, 2018

See below.

Explanation:

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Distance #XA=sqrt(10^2+p^2)#

Distance #AZ=20-p#

Cost of laying cable from #AZ#:

#(20-p)10000#

Cost of laying cable from #XA#:

#(sqrt(10^2+p^2))10000w#

Total cost of laying cable:

#(20-p)10000+(sqrt(10^2+p^2))10000w#

If the cost of laying the cable is 10000C:

Then:

#10000C=(20-p)10000+(sqrt(10^2+p^2))10000w#

Dividing by 10000:

#C=20-p+(sqrt(10^2+p^2))w#

Rearranging:

#C=20-p+wsqrt(100+p^2)#

May 18, 2018

#"see explanation"#

Explanation:

#"we require to find the total length of cable required"#

#"using "color(blue)"Pythagoras' theorem "" in "triangleXYA#

#XA^2=XY^2+YA^2#

#rArrXA=sqrt(10^2+p^2)=sqrt(100+p^2)#

#"cost of XA "=wsqrt(100+p^2)#

#AZ=YZ-YA=20-p#

#rArrC=20-p+wsqrt(100+p^2)#