If $ \sum_{r=0}^{10} \left( 10^{r+1} - 1 \right)$ $\,$\(\binom{10}{r} = \alpha^{11} - 1 \), then $ \alpha $ is equal to :
Given three identical bags each containing 10 balls, whose colours are as follows:
A person chooses a bag at random and takes out a ball. If the ball is Red, the probability that it is from Bag I is $ p $ and if the ball is Green, the probability that it is from Bag III is $ q $, then the value of $ \frac{1}{p} + \frac{1}{q} $ is:
If the system of equation $$ 2x + \lambda y + 3z = 5 \\3x + 2y - z = 7 \\4x + 5y + \mu z = 9 $$ has infinitely many solutions, then $ \lambda^2 + \mu^2 $ is equal to: