Consider the photograph-based family-relation statement: a man says, 'I have no brother or sister, but that man's father is my father's son.' Which statements are correct?
The speaker is his father's son because he has no siblings. Therefore, the photographed man's father is the speaker, so the photograph is of the speaker's son.
A is B's sister. C is B's mother. D is C's father. E is D's mother. How is A related to D?
A is sister of B, so C (mother of B) is mother of A. D is father of C, so A is the granddaughter of D.
Six friends A, B, C, D, E, and F are sitting in a circle facing the center. A is to the immediate left of B. C is between D and E. F is between A and D. Who is sitting 2 places to the right of A? (Give position index 1-6 or person name: write letter of person, e.g., C)
Arrangement going clockwise facing inside: A, F, D, C, E, B. Immediate right of A is B, 2nd right of A is E.
A person walks 10 km North, turns right and walks 15 km, turns right again and walks 10 km, then turns left and walks 5 km. Which statements are correct?
The northward and southward movements cancel. The eastward movements total 15+5=20 km, so the displacement is 20 km east and its magnitude is 20 km.
A person travels 6 km East, then 8 km North. What is the shortest straight-line distance (in km) from the starting point?
Shortest distance = sqrt($6^2 + 8^2)$ = sqrt(36 + 64) = sqrt(100) = 10 km.