JEE Main 2022 · 29 Jun · Shift 2 · Mathematics Q18

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MathematicsSingle correct+4 / -1Question 18 of 90

From the base of a pole of height 20 meter, the angle of elevation of the top of a tower is 60°. The pole subtends an angle 30° at the top of the tower. Then the height of the tower is:

15\sqrt3

20\sqrt3

20+10\sqrt3

Answer and worked solution

Official answer: D

Angles at the top. The line to the tower's foot makes $30°$ with the vertical, and the pole subtends another $30°$ , so the line to the pole's top is $30°$ below horizontal.

Equations. $h=d\sqrt3$ and $h-20=\frac d{\sqrt3}$ : $d=10\sqrt3$ , $h=30$ .

(D)

Topics:Heights and distances

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JEE Main 2022 · 29 Jun · Shift 2, Mathematics question 18