SSC Selection Post 2025 PYQ — Question 42

SSC Selection Post - Graduation Level - 2nd August 2025 - Shift 3 • Quantitative Aptitude • Q42

A hemisphere has radius R. A sphere of maximum possible radius is inscribed in the hemisphere such that it touches the curved surface internally and rests on the hemisphere’s base. Find the ratio of their surface areas.

Show answer & explanation

Correct answer: A

Explanation

Radius of the hemisphere = R

Radius of the sphere = r

Distance from the center of the hemisphere to the center of the sphere = r

Due to internal contact—

R − r = r

R = 2r

r = R/2

Ratio—

3πR² : 4π(R/2)²

3πR² : πR²= 3 : 1