Subject: General Aptitude · Chapter: Volume and Surface Area · Exam: 2010 · Marks: · Difficulty:
Three spheres of radii 3 cm, 4 cm and 5 cm are melted to form a new sphere. Find the radius of the new sphere.
Answer
Answer (as printed):
Explanation
Let the radius of the new sphere be r cm. Then, Volume of new sphere = Sum of volumes of three spheres 4 3 4 3 4 3 4 3 ⇒ πr = π × 3 + π × 4 + π × 5 3 3 3 3 ⇒ r3 = 33 + 43 + 53 = 27 + 64 + 125 = 216 ⇒ r = 3 216 = 6. Hence, radius of new sphere = 6 cm.
Explanation as extracted from the printed page; notation may be imperfect.