A) \[2\sqrt{6}~m\]
B) \[6\sqrt{1.75}~m\]
C) \[4\sqrt{6}~m\]
D) \[5~\sqrt{6}\,m\]
E) None of these
Correct Answer: B
Solution :
Explanation Option [b] is correct. Let the height of the room be 6x and its semi-perimeter be 10x. Area of the four wall \[=2~\times \,6x\times ~10x=120{{x}^{2}}\] Area of the paper needed \[=120{{x}^{2}}-40\] Length of the paper needed = \[\frac{120{{x}^{2}}-40}{1}\] Total cost of the paper \[=10~\times (120~{{x}^{2}}-40)=1700\] \[\Rightarrow 120\,{{x}^{2}}=210\Rightarrow \,{{x}^{2}}=\frac{210}{120}=1.75\Rightarrow x=\sqrt{1.75\,}m\] Therefore, height of the room is \[6\sqrt{1.75}\,m\].You need to login to perform this action.
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