Subject: General Aptitude · Chapter: Volume and Surface Area · Exam: 2007 · Marks: · Difficulty:
The breadth of a room is twice its height and half its length. The volume of the room is 512 cu. m. The length of the room is
(a)16 m
(b)18 m
(c)20 m
(d)32 m
Answer
Answer (as printed): A
Explanation
Let the height of the room be $x$ metres. Then, breadth $=2 x$ metres and length $=4 x$ metres. ∴ Volume of the room $=(4 x \times 2 x \times x) \mathrm{m}^{3}=\left(8 x^{3}\right) \mathrm{m}^{3}$. $$8 x^{3}=512 \Rightarrow x^{3}=64 \Rightarrow x=4 .$$ Length of the room is 16 m.
Explanation as extracted from the printed page; notation may be imperfect.