If $x^{2}-7 x+1=0$, what is the value of $\left(x+\frac{1}{x}\right) ?$

If $\theta$ be acute angle and $\cos \theta=\frac{15}{17}$, then the value of $\cot \left(90^{\circ}-\theta\right)$ is

The difference between a series discount of 20%, 10% and a single discount of 30% is

If $5 \sin ^{2} \theta+3 \cos ^{2} \theta=4$, the value of $\tan \theta$ is

The least number to be subtracted from 16800 to make it a perfect square is

There is a pyramid on a base which is a regular hexagon of side 2a. If every slant edge of this pyramid is of length $\frac{5 a}{2}$, the volume of the pyramid is

A can do a piece of work in 20 days, which B can do in 12 days. B worked at it for 9 days. A can finish the remaining work in

By selling an article for Rs. 2362.5, Neeta’s gain was 12.5%. For how much she has to sell it so as to gain 33.5% ?

If $x+y+z=0, \quad \frac{x^{2} y^{2}+y^{2} z^{2}+z^{2} x^{2}}{x^{4}+y^{4}+z^{4}}=?$

The value of $\cos \left(\frac{\pi}{4}+x\right)+\cos \left(\frac{\pi}{4}-x\right)$ will be