SSC CPO 2024 PYQ — Question 145

SSC CPO - 29 June 2024 Shift 2 • Quantitative Aptitude • Q145

Melting a metal ball of radius 3 units, 27 identical dice and a ball of radius 1 units are made. What is the side of dice?

Show answer & explanation

Correct answer: D

Explanation

The correct answer is option 4 i.e. 1.6 units.

Given that, radius of metal ball = 3 units

Volume of sphere =43πr3{4 \over 3} \pi r^3

Volume of dice = volume of cube = side3

According to the given question,

Volume of metal ball = Volume of 27 dice + Volume of ball

⇒ 43πr13{4 \over 3} \pi r_1^3 = 27(a3)+ 43πr23{4 \over 3} \pi r_2^3

⇒ 43π(r13−r23){4 \over 3} \pi (r_1^3 - r_2^3) = 27a3

⇒ 43×227×(33−13){4 \over 3} \times {22 \over 7} \times (3^3 - 1^3) = 27a3 

⇒ 27a3 = 43×227×26{4 \over 3} \times {22 \over 7} \times 26

⇒ a3 = 4.035

⇒ a = 1.59 ≈ 1.6 units

Hence the side of the dice is 1.6 units.