Question

A tent is in the form of a cylinder of diameter 4.2 m and height 4m, surmounted by a cone of equal base and height 2.8 m. find the cost of canvas for making the tent at Rs. 100 per sq.m.

• A. Rs 6590
• B. Rs 7590
• C. Rs 8590
• D. Rs 9876

Answer 1

The correct option is B

Rs 7590

The total surface area of the tent:

$T=2\pi r{h}_1+\pi rl$

$\pi =\frac{22}{7};r=2.1m$

$h_1=heightofthecylinder=4m$

$h_2=heightofthecone=2.8m$

$l=slantheightofthecone=\sqrt{{2.8}^2+{2.1}^2}=3.5m$

So,

$T=(2\times \frac{22}{7}\times 2.1\times 4+\frac{22}{7}\times 2.1\times 3.5)m^2=75.9m^2$

Therefore the cost of canvas for making the tent at Rs 100 per sq meter is Rs 7590.