Height and Distance Questions for Competitive Exams
An observer on the top of a mountain, 500 m above the sea level, observes the angles of depression of the two boats in his same place vision to be 45 ° and 30 ° respectively. Then the distance between the boats, if the boats are on the same side of the mountain, is
(A) 366 m
(B) 699 m
(C) 456 m
(D) 584 m
Correct Answer : A
From the peak of a hill which is 300m high, the angle of depression of two sides of a bridge lying on a ground are 45° and 30° (both ends of the bridge are on the same side of the hill). Then the length of the bridge is
(A) 300√3 m
(B) $${300\over√3}m $$
(C) 300(√3-1) m
(D) 300(√3+1) m
Correct Answer : C
An Aeroplan is flying horizontally at a height of 1.8 km above the ground. The angle of elevation of plane from point X is 60° and after 20 seconds, its angle of elevation from X becomes 30°, If point X is on ground, then what is the speed (in km / hr.) of Aeroplan?
(A) 201√3
(B) 305√3
(C) 216√3
(D) 105√3
Correct Answer : C
A straight tree breaks due to storm and the broken part bends so that the top of the tree touches the ground making an angle of 30 ° with the ground. The distance from the foot of the tree to the point, where the top touches the ground is 10m. Find the total height of the tree
(A) 10(√3+1) m
(B) 10(√3-1) m
(C) 10 √3 m
(D) $${10√3 \over3}m$$
Correct Answer : C
The angle of elevation of sun changes from 30 ° to 45 °, the length of the shadow of a pole decreases by 4 meters, the height of the pole is (Assume √3 = 1.732)
(A) 3.648 m
(B) 5.464 m
(C) 1.464 m
(D) 9.464 m
Correct Answer : B
The upper part of a tree is broken over by the wind makes an angle of 60 ° with the ground. The distance between the root and the point where top of the tree touches the ground is 25 metres. What was the height (in metres) of the tree?
(A) 98.25
(B) 120.24
(C) 84.14
(D) 93.3
Correct Answer : D
129 meter from the foot of a cliff on level of ground, the angle of elevation of the top of cliff is 30 °. The height of this cliff is
(A) 43√3 metre
(B) 47 √3 metre
(C) 50 √3 metre
(D) 45 √3 metre
Correct Answer : A
The angle of elevation of ladder leaning against a house is 60° and the foot of the ladder is 6.5 meters from the house. The length of the ladder is
(A) √13 meters
(B) 3 meters
(C) √3 meters
(D) 13 meters
Correct Answer : D
A Navy captain going away from a lighthouse at the speed of 4[(73) -1] m/s. He observes that it takes him 1 minute to change the angle of elevation of the top of the lighthouse from 60 ° to 45 °. What is the height (in meters) of the lighthouse?
(A) 360√3
(B) 280√2
(C) 240√3
(D) 480[(√3)-1]
Correct Answer : C
A person from the top of a hill observes a vehicle moving towards him at a uniform speed. It takes 10 minutes for the angle of depression to change from 45 ° to 60 °. After this the time required by the vehicle to reach the bottom of the hill is
(A) 13 min 40 sec
(B) 14 min 24 sec
(C) 12 min 20 sec
(D) 13 min
Correct Answer : A