$\frac{(272-32)(124+176)}{17 \times 15-15} = ?$

What will come in the place of the question mark $(?)$ in the following equation?
$(23.1)^{2} + (48.6)^{2} - (39.8)^{2} = ? + 1147.69$

If $\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right) \ldots\left(1-\frac{1}{70}\right)=\frac{x}{70},$ then what is the value of $x ?$

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?

The correct expression of $5 . \overline{45}$ in the fractional form is

What mathematical operation should come at the place of $?$ in the equation $2 ? 6 - 12 \div 4 + 2 = 11$?