Question

The volume of rectangular block of stone is $4410368d{m}^2$. Its dimensions are in the ratio of $3:2:1$. If its entire surface is polished at $2paiseperd{m}^2$, then the total cost will be

• A. $Rs63.36$
• B. $Rs63.00$
• C. $Rs31.50$
• D. $noneofthese$

Answer 1

Answer: (A)

$Rs63.36$

Volume = 4410368

Let ratio is x

$\begin{array}{c}l=3x,b=2x,h=1x\\ V=4410368\\ 3x\times 2x\times x=4410368\\ 6x^2=4410368\\ x^3=\frac{4410368}{6}\\ x=90.25\\ l=3\times 90.25=240.75\\ b=2\times 90.25=180.50\\ h=1\times 90.25=90.25\\ Area=2\left(lb+bh+hl\right)\\ =2\left[240.75\times 180.50+180.50\times 90.25+90.25\times 240.75\right]\\ =162946.375\\ costof{\left(dx\right)}^2=2pairs\\ =\frac{2}{100}Rs\\ costof162946.375=\frac{2}{100}\times 162946.375\\ =3258.9Rs.\end{array}$