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UKMT Junior Kangaroo, 2021

Number theory Difficulty 2.0 Junior Find the answer United Kingdom

The houses on the south side of Crazy Street are numbered in increasing order starting at 1 and using consecutive odd numbers, except that odd numbers that contain the digit 3 are missed out. What is the number of the 20th house on the south side of Crazy Street?

(A) $41$ (B) $49$ (C) $51$ (D) $59$ (E) $61$

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