List of practice Questions

Let \( ABCD \) be a tetrahedron such that the edges \( AB \), \( AC \), and \( AD \) are mutually perpendicular. Let the areas of the triangles \( ABC \), \( ACD \), and \( ADB \) be 5, 6, and 7 square units respectively. Then the area (in square units) of the \( \triangle BCD \) is equal to:

Let \( R \) be a relation defined on a set \( \mathbb{N} \) of natural numbers such that \( R = \{(x, y) : xy \text{ is a square of a natural number}, x, y \in \mathbb{N} \} \). Determine if the relation \( R \) is an equivalence relation.

Match the following:

Column I	Column II
(a) Lecture Method	(II) Teacher-centered, focuses on delivery
(b) Demonstration Method	(I) Learning by doing
(c) Project Method	(III) Students explore real-life problems
(d) Heuristic Method	(IV) Learning through discovery

Four players — W, X, Y, Z — play a round-robin tournament (each plays each once).
A win gives 2 points, loss 0.
W scores more points than X.
Y wins exactly one match.
Z does not lose to X.
How many distinct possible point-tables exist for the four players?