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UKMT Junior Mathematical Challenge, 2016

Geometry Difficulty 2.0 Junior Find the answer United Kingdom

In the diagram, $AB = AC$ and $D$ is a point on $AC$ such that $BD = BC$ . Angle $BAC$ is $40^\circ$ . What is angle $ABD$ ?

(A) $15^\circ$ (B) $20^\circ$ (C) $25^\circ$ (D) $30^\circ$ (E) $35^\circ$

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