JEE Main 2021MathematicsHeights and DistancesEasyMCQ

JEE Main 2021 — Heights and Distances Question with Solution

JEE Main 2021 (24 Feb Shift 2)

Question

The angle of elevation of a jet plane from a point A on the ground is 60°. After a flight of 20 seconds at the speed of 432 km/hour, the angle of elevation changes to 30°. If the jet plane is flying at a constant height, then its height is:

Choose an option

Show full solutionCorrect option: A
Correct answer
A12003 m

Step-by-step explanation

tan60°=hy

3=hy⇒h=3y …1

tan30°=hx+y

13=hx+y⇒3h=x+y …2

Speed 432 km h-1⇒432×2060×60⇒125 km

3h=125+y

3h-125=y

from 1

h=33h-125

h=3 h-1235

h=635 km

h=12003 m

Practice this on the real CBT interface

Solve this JEE Main question (and the rest of the Heights and Distances chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.

Solve interactively →

About this question

This is a previous-year question from JEE Main 2021, covering the Heights and Distances chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.