7 boys and 5 girls are to be seated around a circular table such that no two girls sit together is?
Let $y=f(x)$ represent a parabola with focus $\left(-\frac{1}{2}, 0\right)$ and directrix $y=-\frac{1}{2}$ Then $S=\left\{x \in R : \tan ^{-1}(\sqrt{f(x)})+\sin ^{-1}(\sqrt{f(x)+1})=\frac{\pi}{2}\right\}$ :
The number of functions \(f:\{1,2,3,4\} \rightarrow\{ a \in: Z|a| \leq 8\}\) satisfying \(f(n)+\frac{1}{n} f( n +1)=1, \forall n \in\{1,2,3\}\) is
Number of 4-digit numbers that are less than or equal to 2800 and either divisible by 3 or by 11 , is equal to