Multiple choice

Two soild spheres of gold having diameters 3 cm. and 4 cm. are melt and then cost into one big sphere of gold. If the radius of this sphere is x, then what is the value of x3 ?

  1. 125 cu.cm.

  2. 15.625 cu.cm.

  3. 11.375 cu.cm.

  4. 9.875 cu.cm.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Combined volume = (4/3)π(1.5)³ + (4/3)π(2)³ = (4/3)π(3.375 + 8) = (4/3)π(11.375). For big sphere: (4/3)πx³ = (4/3)π(11.375), so x³ = 11.375 cu.cm.