Worked examples: prove the family path

The same family, two viewpoints

A cousin is a child of your parent’s sibling. The precise path matters more than whether two names are drawn on the same row.

Our example gives these facts: A is the mother of B and C; B is D’s father; C is E’s mother; E is C’s daughter. B and C explicitly share mother A. D’s gender is not given.

Text map: A → B → D and A → C → E. Every arrow means parent → child. B is male, C and E are female. To identify E’s relation to D, stand at D: father B → B’s sister C → her daughter E. E is D’s paternal aunt’s daughter, a cousin.

Now reverse the question. To identify D’s relation to E, stand at E: mother C → C’s brother B → B’s child D. D is E’s maternal uncle’s child. We cannot choose son or daughter without D’s gender.

“Father’s brother” does not by itself tell us whether that uncle is older or younger than the father. Avoid choosing an age-specific Hindi term without that extra fact.

Work the path, not the page position

Worked path for E to D: D → father B → B’s sister C → C’s daughter E. Result: paternal aunt’s daughter.

Worked reverse path for D to E: E → mother C → C’s brother B → B’s child D. Result: maternal uncle’s child. D’s gender is missing, so stop at “child”.

These paths refer to the explicitly described shared-mother map below. The backward/sideways movements are your route through the family, not new parent arrows.

Finish this solution

If D is additionally stated to be male, the reverse answer becomes “maternal uncle’s ____”. The missing word is “son”. Only one new fact changed; the whole map did not need redrawing.

Catch the common error

“D and E are on the same row, therefore siblings” is invalid. The given map makes their parents siblings. Children of those two sibling branches are cousins.

Now answer the checks, without copying the worked label when the viewpoint changes.

Now take the separate practice

Open this lesson’s Practice test: five new checks, about eight minutes, with explanations after answering. This is a low-stakes learning check, not an official SSC paper. Try without the notes, then return to the exact step that caused an error. The optional time estimate is not an exam speed target.

Comparison note: these prototype modules use parallel versions of the same skills. Repeated exposure can improve your score, so this is a format comparison, not a controlled experiment proving which method is best.

Feedback-design reference: Khan Academy’s Perseus exercise editor and renderer. These worked examples and questions are original, using PPDF’s existing quiz components rather than imported code.