UKMT Grey Kangaroo, 2022

Algebra Difficulty 1.0 Junior Find the answer United Kingdom

Werner wrote a list of numbers with sum 22 on a piece of paper. Ria then subtracted each of Werner's numbers from 7 and wrote down her answers. The sum of Ria's numbers was 34. How many numbers did Werner write down?

(A) $7$ (B) $8$ (C) $9$ (D) $10$ (E) $11$

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