Quantitative Aptitude Ques 115
Question: The length of canvas 75 cm wide required to build a conical tent of height 14 m and the floor area $ 346.5,m^{2}, $ is
Options:
A) 665 m
B) 770 m
C) 490 m
D) 860 m
Show Answer
Answer:
Correct Answer: B
Solution:
- Given, floor area $ 346.5m^{2} $
$ \therefore $ $ \pi r^{2}=346.5 $
$ \Rightarrow $ $ r^{2}=\frac{346.5}{22}\times 7 $
$ \Rightarrow $ $ r^{2}=11025 $
$ \Rightarrow $ $ r=10.5,m $
Now, $ l=\sqrt{r^{2}+h^{2}}=\sqrt{{{(10.5)}^{2}}+{{(14)}^{2}}} $
$ =\sqrt{110.25+196}=\sqrt{306.25}=17.5,m $
$ \therefore $ Area of canvas = Area of cone
$ \Rightarrow $ $ l\times b=\pi rl $
$ \Rightarrow $ $ l\times \frac{75}{100}=\frac{22}{7}\times 10.5\times 17.5 $
$ \Rightarrow $ $ l=\frac{22\times 10.5}{7\times 75}\times 17.5\times 100 $
$ \therefore $ $ l=770 $
$ \therefore $ Length of canvas = 770 m
BETA
