Question : Let $a=\frac{1}{2-\sqrt{3}}+\frac{1}{3-\sqrt{8}}+\frac{1}{4-\sqrt{15}}$ then we have:
Option 1: $a<18 \text{ but } a\neq 9$
Option 2: $a>18$
Option 3: $a=18$
Option 4: $a=9$
Recommended: How to crack SSC CHSL | SSC CHSL exam guide
Don't Miss: Month-wise Current Affairs | Upcoming government exams
New: Unlock 10% OFF on PTE Academic. Use Code: 'C360SPL10'
Correct Answer: $a<18 \text{ but } a\neq 9$
Solution : $a=\frac{1}{2-\sqrt{3}}+\frac{1}{3-\sqrt{8}}+\frac{1}{4-\sqrt{15}}$ $=\frac{1}{2-\sqrt{3}}\times\frac{2+\sqrt{3}}{2+\sqrt{3}}+\frac{1}{3-\sqrt{8}}\times\frac{3+\sqrt{8}}{3+\sqrt{8}}+\frac{1}{4-\sqrt{15}}\times\frac{4+\sqrt{15}}{4+\sqrt{15}}$ $=\frac{2+\sqrt{3}}{4-3}+\frac{3+\sqrt{8}}{9-8}+\frac{4+\sqrt{15}}{16-15}$ $=2+\sqrt{3}+3+\sqrt{8}+4+\sqrt{15}$ $=9+\sqrt{3}+\sqrt{8}+\sqrt{15}$ $<9+2+3+4$ $<18$ Hence, the correct answer is $a<18 \text{ but } a\neq 9$.
Candidates can download this e-book to give a boost to thier preparation.
Application | Eligibility | Admit Card | Answer Key | Preparation Tips | Result | Cutoff
Question : Let $\sqrt[3]{a}=\sqrt[3]{26}+\sqrt[3]{7}+\sqrt[3]{63}$. Then:
Option 1: $a<729$ but $a>216$
Option 2: $a<216$
Option 3: $a>729$
Option 4: $a = 729$
Question : If $\sec A=\frac{9}{4}$, then what is the value of $\cot A$?
Option 1: $\frac{4}{\sqrt{65}}$
Option 2: $\frac{9}{\sqrt{65}}$
Option 3: $\frac{\sqrt{65}}{9}$
Option 4: $\frac{\sqrt{65}}{4}$
Question : If $\theta$ is an acute angle and $\sin \theta \cos \theta=2 \cos ^3 \theta-\frac{1}{4} \cos \theta$, then the value of $\sin \theta$ is:
Option 1: $\frac{\sqrt{15}-1}{8}$
Option 2: $\frac{\sqrt{15}-1}{4}$
Option 3: $\frac{\sqrt{15}+1}{4}$
Option 4: $\frac{\sqrt{15}-1}{2}$
Question : If $a=\frac{1}{a-\sqrt{6}}$ and $(a>0)$, then the value of $\left(a+\frac{1}{a}\right)$ is:
Option 1: $\sqrt{6}$
Option 2: $\sqrt{10}$
Option 3: $\sqrt{15}$
Option 4: $\sqrt{7}$
Question : If $\sin(A+B)=\sin A\cos B+\cos A \sin B$, then the value of $\sin75°$ is:
Option 1: $\frac{\sqrt{3}+1}{\sqrt{2}}$
Option 2:
$\frac{\sqrt{2}+1}{2\sqrt{2}}$
Option 3:
$\frac{\sqrt{3}+1}{2\sqrt{2}}$
Option 4:
$\frac{\sqrt{3}+1}{2}$
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile