The real variables $x, y, z$, and the real constants $p, q, r$ satisfy

$\frac{x}{pq - r^2} = \frac{y}{qr - p^2} = \frac{z}{rp - q^2}$

Given that the denominators are non-zero, the value of $px + qy + rz$ is

Take two long dice (rectangular parallelepiped), each having four rectangular faces labelled as 2, 3, 5, and 7. If thrown, the long dice cannot land on the square faces and has 1/4 probability of landing on any of the four rectangular faces. The label on the top face of the dice is the score of the throw.

If thrown together, what is the probability of getting the sum of the two long dice scores greater than 11?

In the given text, the blanks are numbered (i)–(iv). Select the best match for all the blanks.

Prof. P __(i)__ merely a man who narrated funny stories. __(ii)__ in his blackest moments he was capable of self-deprecating humor.

Prof. Q __(iii)__ a man who hardly narrated funny stories.__(iv)__ in his blackest moments was he able to find humor.

How many combinations of non-null sets A, B, C are possible from the subsets of {2, 3, 5} satisfying the conditions: (i) A is a subset of B, and (ii) B is a subset of C?