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UKMT Junior Mathematical Challenge, 2015

Number theory Difficulty 2.0 Junior Find the answer United Kingdom

Digits on a calculator are represented by a number of horizontal and vertical illuminated bars. The digits and the bars which represent them are shown in the diagram. How many digits are both prime and represented by a prime number of illuminated bars?

(A) $0$ (B) $1$ (C) $2$ (D) $3$ (E) $4$

Figure for this problem

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