Blood relations, directions, syllogisms and seating

These four question types become easy when you stop solving them in your head and draw a small diagram. A ten-second sketch usually beats a minute of mental juggling.

Blood relations

Work from the end of the sentence back to the speaker. For "He is the son of my mother's only brother", start with "my mother", then her brother (my maternal uncle), then his son (my cousin).

• Draw generations on different levels: grandparents at the top, children below.
• Mark gender with + and - so you do not assume it.
• Do not decide a gender the question has not told you. If only "B's child" is given, you cannot say son or daughter.

Direction sense

Draw a compass and the path. Right turns are clockwise and left turns are anticlockwise, whatever direction the person is facing.

Start -> 5 km N -> right (E) 3 km -> right (S) 5 km
Net: N 5 - S 5 = 0,  E 3  => 3 km east of start

For distance from the start, add opposite directions as plus and minus. If both a north-south and an east-west distance remain, use the Pythagoras rule: a 3-4 movement gives 5.

Syllogisms

Draw circles for each group. A conclusion follows only if it is true in every possible drawing, not just one.

1. "All A are B": circle A inside circle B.
2. "Some A are B": the circles overlap.
3. "No A is B": the circles are separate.

Common traps: "Some A are B" does not mean "Some A are not B", and "All A are B" does not mean "All B are A". If all pens are books, then some books are pens, but not all books.

Seating arrangement basics

Start with the fixed facts, such as who sits at an end, then add the conditions that link two people. For people facing north, their right is your right as you look at the diagram. When people face south, left and right reverse.

Once you have one arrangement, check every condition against it. If two arrangements fit, look for the condition you have not used yet.

Checklist: draw first, place fixed facts first, test each conclusion against every possible case, and read the question again before choosing.