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QJEEM23Mab0e5: JEE Main 2023 Mathematics - Class 12 JEEM23Mab0e5 Solution: The angle of elevation of the top of a tower from the feet of…

The angle of elevation of the top P\mathrm{P} of a tower from the feet of one person standing due South of the tower is 45∘45^{\circ} and from the feet of another person standing due west of the tower is 30∘30^{\circ} . If the height of the tower is 5 meters, then the distance (in meters) between the two persons is equal to

Multiple Choice Options

  • A 10
  • B 525\frac{5}{2} \sqrt{5}
  • C 555 \sqrt{5}
  • D 5

Step-by-Step Verified Solution

Let's denote the person standing due south as S and the one standing due west as W. Also, let the tower be at point T.

From person S's perspective, we have a right triangle △SPT\triangle SPT . The height of the tower PT is given as 5m, which is the opposite side for angle S. The angle at S is 45∘45^\circ . From the tangent trigonometric ratio, we have :

tan⁡45∘=PTST=5ST\tan{45^\circ} = \frac{PT}{ST} = \frac{5}{ST}

Since tan⁡45∘=1\tan{45^\circ}=1 , we get ST=5ST = 5 m.

Similarly, from person W's perspective, we have a right triangle △WPT\triangle WPT . The angle at W is 30∘30^\circ . From the tangent trigonometric ratio, we have:

tan⁡30∘=PTWT=5WT\tan{30^\circ} = \frac{PT}{WT} = \frac{5}{WT}

Since tan⁡30∘=13\tan{30^\circ}=\frac{1}{\sqrt{3}} , we get WT=53WT = 5\sqrt{3} m.

Since S and W are perpendicular to each other (one is due south and the other is due west), △SWT\triangle SWT forms a right triangle.

We can find SWSW (the distance between the two people) using the Pythagorean theorem:

SW2=ST2+WT2=52+(53)2=25+75=100SW^2 = ST^2 + WT^2 = 5^2 + (5\sqrt{3})^2 = 25 + 75 = 100

So, SW=100=10SW = \sqrt{100} = 10 m.

Hence, the correct answer is 10 meters, which corresponds to Option A.

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