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UKMT Senior Mathematical Challenge, 2021

Combinatorics Difficulty 2.0 Junior Find the answer United Kingdom

An array of $25$ equally spaced dots is drawn in a square grid as shown. Point $O$ is in the bottom left corner. Linda wants to draw a straight line through the diagram which passes through $O$ and exactly one other point. How many such lines can Linda draw?

(A) $4$ (B) $6$ (C) $8$ (D) $12$ (E) $24$

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