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UKMT Pink Kangaroo, 2022

Combinatorics Difficulty 2.0 Junior Find the answer United Kingdom

A certain city has two types of people: the `positives', who only ask questions for which the correct answer is ``yes'' and the `negatives' who only ask questions for which the correct answer is ``no''. When Mo and Bo met Jo, Mo asked, ``Are Bo and I both negative?'' What can be deduced about Mo and Bo?

(A) Both positive (B) Both negative (C) Mo negative, Bo positive (D) Mo positive, Bo negative (E) impossible to determine

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