1. Profit (P) is the difference between selling price (S) and cost price (C).   Hint Hint       2. Circumference (C) of a circle is (22/7) times the diameter (d).   Hint       3. Surface area (S) of a cube equals six times the square of an edge (a) of the cube.   Hint       4. Weight (W) is the product of the mass (m) of a body and the acceleration due to gravity (g).   Hint       5. Perimeter (P) of a square is four times the length of a side (a).   Hint       6. The sum of the magnitude of the interior angles (A) of a convex polygon divided by 180 equals the number of sides (s) decreased by 2.   Hint       7. Pressure (P) is the force (F) divided by the area (A).   Hint