Question : If 25% of 400 + 35% of 1260 + 27% of 1800 = 1020 + $x$, then the value of $x$ lies between:

Option 1: 6 to 10

Option 2: 0 to 5

Option 3: 11 to 15

Option 4: 16 to 20

Question : If $x\left(5-\frac{2}{x}\right)=\frac{5}{x}$, then the value of $x^2+\frac{1}{x^2}$ is:

Option 1: $\frac{54}{25}$

Option 2: $\frac{53}{28}$

Option 3: $\frac{53}{27}$

Option 4: $\frac{54}{23}$

Question : If $\sec x+\cos x=2$, then the value of $\sec^{16} x+\cos^{16} x$ will be:

Option 1: $\sqrt3$

Option 2: $2$

Option 3: $1$

Option 4: $0$

Question : If $x^2-2\sqrt{10}x+1=0$, what is the value of $(x-\frac{1}{x})$?

Option 1: $4$

Option 2: $6$

Option 3: $3$

Option 4: $5$

Question : If $x^4+x^{-4}=47, x>0$, then what is the value of $x+\frac{1}{x}-2?$

Option 1: 1

Option 2: 0

Option 3: 5

Option 4: 3

Question : If $x^2-5 x+1=0$, then the value of $\left(x^4+\frac{1}{x^2}\right) \div\left(x^2+1\right)$ is:

Option 1: 21

Option 2: 22

Option 3: 25

Option 4: 24