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UKMT Junior Mathematical Challenge, 2021

Number theory Difficulty 2.0 Junior Find the answer United Kingdom

Alex has a pile of two pence coins. She swapped exactly half of them for the same number of 10p coins. Now she has £4.20. How much money did Alex have initially?

(A) $42$ p (B) $84$ p (C) £ $1.12$ (D) £ $1.40$ (E) £ $1.68$

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