Maths Olympiad Prep

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Number theory Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

Two of the following four facts about a positive integer NN are true and two are false.

NN is divisible by 5
NN is divisible by 11
NN is divisible by 55
NN is less than 10

What is the value of NN?

(A) 55 (B) 1010 (C) 1111 (D) 5555 (E) 110110

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Source: UK Mathematics Trust, licensed © UK Mathematics Trust; past papers published free at ukmt.org.uk. Statement reproduced verbatim; metadata (topic, difficulty) added by this project. Solutions are the publisher's, linked not copied.