If $\frac{a}{a+b}=\frac{17}{23},$ what is $\frac{a+b}{a-b}$ equal to?

In a college,$\frac{1}{5}$ of the girls and $\frac{1}{8}$ of the boys took part in a social camp. What part of the total number of students in the college took part in the camp?

If $x = \sqrt{\frac{2+\sqrt{3}}{2-\sqrt{3}}}$,then what is the value of $(x^{2} - x - 9)$?

If the difference between $\frac{4}{5}$ part and $\frac{3}{4}$ part of a number is $4,$ what is the number?

If $(2+\sqrt{3}) a=(2-\sqrt{3}) b=1,$ then the value of $\frac{1}{a}+\frac{1}{b}$ is

Manmohan spends $\frac{1}{5}$ part of his money as pocket money and $\frac{4}{5}$ of the remainder in other affairs. If he is left with $Rs.\, 48$ per month,what is his monthly income? (in $Rs.$)