SSC CGL 2025 PYQ — Question 72

SSC CGL - 24 Sep 2025 - Shift 1 • Quantitative Aptitude • Q72

A man observes the top of a pole with an angle of elevation of 45°. He walks 15 m towards the pole, and the angle of elevation becomes 60°. What is the height of the pole?

Show answer & explanation

Correct answer: D

Explanation

The correct answer is option 4 i.e.  15(3+3)2\frac{15(3 + \sqrt{3})}{2} m.

Let the height of the pole = h meters

Let the initial distance from the man to the pole = d meters

From the first observation: tan⁡45∘=hd\tan 45^\circ = \frac{h}{d}

⇒ 1 = h/d

⇒ h = d

After walking 15 m towards the pole: New distance = d - 15 meters

Second observation: tan⁡60∘=hd−15\tan 60^\circ = \frac{h}{d - 15}

⇒ 3=hd−15\sqrt{3} = \frac{h}{d - 15}

⇒ 3=dd−15\sqrt{3} = \frac{d}{d - 15}

⇒ 3(d−15)=d\sqrt{3}(d - 15) = d

⇒ 3d−153=d\sqrt{3}d - 15\sqrt{3} = d

⇒ √3d - d = 15√3

⇒ d(√3 - 1) = 15√3

⇒ d=1533−1=153(3+1)3−1=15(3+3)2d = \frac{15\sqrt{3}}{\sqrt{3} - 1}= \frac{15\sqrt{3}(\sqrt{3} + 1)}{3 - 1}= \frac{15(3 + \sqrt{3})}{2} m