SATHEE: Quantitative Aptitude Ques 291

Quantitative Aptitude Ques 291

Question: A large cube is formed by melting three smaller cubes of 3 cm, 4 cm and 5 cm side. What is the ratio of the total surface areas of the small cubes and the larger cube?

Options:

A) 2 : 1

B) 3 : 2

C) 25 : 18

D) 27 : 20

Show Answer

Answer:

Correct Answer: C

Solution:

Volume of largest cube $ =3^{3}+4^{3}+5^{3} $ $ =27+64+125=216,cm^{3} $

$ \therefore $ Side of largest cube $ =\sqrt[3]{216}=6,cm $ Total surface area of small cube

$ \therefore $ Required ratio $ \text{=}\frac{Total,surface,area,of,small,cube}{Total,surface,area,of,largest,cube} $ $ \text{=},\frac{6\times {{(3)}^{2}}+6\times {{(4)}^{2}}+6\times {{(5)}^{2}}}{6\times {{(6)}^{2}}} $ $ =,\frac{9+16+25}{36}=\frac{50}{36}=\frac{25}{18}=25:18 $

Quantitative Aptitude Ques 290

Quantitative Aptitude Ques 292

Quantitative Aptitude Ques 291

Question: A large cube is formed by melting three smaller cubes of 3 cm, 4 cm and 5 cm side. What is the ratio of the total surface areas of the small cubes and the larger cube?

Options:

Answer:

Solution:

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