Question : A man standing on the bank of a river observes that the angle subtended by a tree on the opposite bank is 60°. When he retreats 36 m from the bank, he finds that the angle is 30°. The breadth of the river is:
Option 1: 15 metres
Option 2: 18 metres
Option 3: 16 metres
Option 4: 11 metres
Latest: SSC CGL preparation tips to crack the exam
Don't Miss: SSC CGL complete guide
New: Unlock 10% OFF on PTE Academic. Use Code: 'C360SPL10'
Correct Answer: 18 metres
Solution : Let the breadth of the river be AC = $x$ metres Clearly $\tan 30°=\frac{AB}{AD}=\frac{h}{x+36}$ ⇒ $\tan 60°=\frac{AB}{AD}=\frac{h}{x}$ ⇒ $\frac{\tan 60°}{\tan 30°}=\frac{\frac{h}{x}}{\frac{h}{x+36}}$ ⇒ $\frac{\sqrt3}{\frac{1}{\sqrt3}}=\frac{x+36}{x}$ ⇒ $3x=x+36$ ⇒ $x=18$ m Hence, the correct answer is 18 metres.
Candidates can download this ebook to know all about SSC CGL.
Answer Key | Eligibility | Application | Selection Process | Preparation Tips | Result | Admit Card
Question : A man standing on the bank of a river observes that the angle of elevation of the top of a tree just on the opposite bank is $60°$. But the angle of elevation is $30°$ from a point which is at a distance $20\sqrt{3}$ ft away from the bank. Then the
Question : A coconut tree swings with the wind in such a manner that the angle covered by its trunk is 18°. If the topmost portion of the tree covers a distance of 44 metres, find the length of the tree. ( $\tan 18°$ = 0.3249).
Question : The vertical angle $\angle A$ of an isosceles $\triangle ABC$ is three times the angle B on it. The measure of the $\angle A$ is:
Question : A man on the top of a tower, standing on the seashore, finds that a boat coming towards him takes 10 minutes for the angle of depression to change from 30° to 60°. How soon does the boat reach the seashore?
Question : In $\triangle $ABC, D is a point on side BC such that $\angle$ADC = 2$\angle$BAD. If $\angle$A = 80° and $\angle$C = 38°, then what is the measure of $\angle$ADB?
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile