Subject: General Aptitude · Chapter: Volume and Surface Area · Exam: · Marks: · Difficulty:
Each side of a cube is decreased by 25\%. Find the ratio of the volumes of the original cube and the resulting cube. [SSC-CHSL (10+2) Exam, 2015]
(a)64 : 1
(b)27 : 64
(c)64 : 27
(d)8 : 1
Answer
Answer (as printed): C
Explanation
Let the side of cube = 10cm ∴ Original volume $=10 \times 10 \times 10=1000 \mathrm{cm}^{3}$ Now, side of new cube $=10-25 \%$ of $10=7.5 \mathrm{cm}$ ∴ New volume $=7.5 \times 7.5 \times 7.5=421.875 \mathrm{cm}^{3}$ ∴ Required Ratio $=\frac{1000}{421.875}=\frac{1000000}{421875}=\frac{64}{27}=64: 27$