Question
A Navy captain going away from a lighthouse at the speed of 4[(√3) – 1] m/s. He observes that it takes him 1 minute to change the angle of elevation of the top of the lighthouse from 60o to 45o. What is the height (in metres) of the lighthouse?
Let height is H tan 600 = H / BD = BD = H / tan600 [BD = H / √3 tan 450 = AB / BC = AB = BC, BC = H 4(√3 – 1) m/s speed Time = 1 minute 60 Second Distance = Speed × Time = 4√3 – 1) × 60 = 240√3 – 240 CD = 240√3 – 60 CD = H – H/√3 = 240√3 – 240 H(√3 – 1) = 240√3(√3 – 1) H = 240√3 mMore Height and Distance Questions
- There are two houses of the same height on both sides of a 40-meter wide road. From a point on the road, elevation angles of the houses are 30° and 60° res...
- The shadow of a pole 24m long is 56m. Then what will be the approximate shadow of building 40m high at the similar situation?
- From a point situated at some distance from the base of a pillar, the angle of elevation of the top of the pillar is found to be 45 degrees. After walking ...
- The length of the shadow of a vertical tower increases by 8 m on horizontal ground when the height of the sun changes from 45° to 30 ° , then find the heig...
- The angle of elevation of an aeroplane from a point on the ground is 60°. After 15 seconds flight the elevation changes to 30°, if the aeroplane is flying ...
- Two men are on opposite sides of a tower of 75 m height. If they measure the elevation of the top of the tower as 30deg; and 45deg; respectively then the d...
- From a point on level ground, the angle of elevation of the top of a vertical tower is 30°. On moving 30 m closer to the tower, the angle of elevation beco...
- A man 3 m tall is 19 m away from a tower 22 m high. Determine the angle of elevation of the top of the tower from the eye of the observer.
- From the top of a straight pillar 20 meters high, the angle of elevation of the top of a straight tower was 45°. If the tower was 70 meters high, then at w...
- At a point 20 metres away from the base of a 20√3, metres high house, the angle of elevation of the top is
Hey! Ask a query
Please enter email id
The email must be a valid email address.
Please enter Mobile Number
Please enter valid Mobile Number
Please enter your Doubt
Think You're Ready for RBI Grade B?
RBI Grade B 2026 Phase 1 Memory Based Paper
- 200 Questions with Detailed Solutions
- Section-wise Coverage (GA, English, Quant & Reasoning)