A) 2420 sq cm
B) 3320 sq cm
C) 4320 sq cm
D) 5320 sq cm
Correct Answer: C
Solution :
| [c] Let the length, breadth and height of a rectangular parallelepiped be. l, b and h, respectively. Then,\[l=3b=5h=a\,\,(let)\] \[\Rightarrow \] \[l=a,\]\[b=\frac{a}{3},\]\[h=\frac{a}{5}\] Given, volume of parallelepiped\[=14400\,c{{m}^{3}}\] \[\Rightarrow \] \[a\times \frac{a}{3}\times \frac{a}{5}=14400\] \[\Rightarrow \] \[{{a}^{3}}=14400\times 15\] \[\therefore \] \[a=\sqrt[3]{14400\times 15}=60\,cm\] Total surface area of parallelepiped \[=2\,(lb+bh+hl)\] \[=2\,(60\times 20+20\times 12+12\times 60)\] \[=4320\,c{{m}^{2}}\] |
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