JEE Main 2018MathematicsHeights and DistancesEasyMCQ

JEE Main 2018 — Heights and Distances Question with Solution

JEE Main 2018 (16 Apr Online)

Question

A man on the top of a vertical tower observes a car moving at a uniform speed towards the tower on a horizontal road. If it takes 18 min for the angle of depression of the car to change from 30° to 45°, then the time taken (in min) by the car to reach the foot of the tower is

Choose an option

Show full solutionCorrect option: D
Correct answer
D91+3

Step-by-step explanation



Let length of tower be h.

⇒AC′=AB=h

And AC=ABcot30°=3h

⇒CC′=3-1h

Time taken by car form C C'=18 min

⇒Time take by car to reach the foot of the tower

=183-1 min

=93+1 min

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 2018, 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.