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UKMT Junior Kangaroo, 2015

Combinatorics Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

The diagram on the right shows a large triangle divided up into squares and triangles. $S$ is the number of squares of any size in the diagram and $T$ is the number of triangles of any size in the diagram. What is the value of $S \times T$ ?

(A) $30$ (B) $35$ (C) $48$ (D) $70$ (E) $100$

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