<PRE><B>Question 1062672</B>

I think you made a mistake in your calculation because the question asks for foreign coins not from Mexico, as a fraction of the _entire_ collection.
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Let C = number of coins in entire collection
Let F = number of foreign coins  (F = (1/4)C)

number of foreign coins from Mexico = (2/5)F = (2/5)(1/4)C = (2/20)C = (1/10)C

The question asks for the fraction of the (entire) collection that are foreign coins not from Mexico.

That fraction is  F - (1/10)C =  (1/4)C - (1/10)C = (5/20)C - (2/20)C = (3/20)C

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Check:    (3/20)C + (2/20)C = (5/20)C = (1/4)C = F  = number of foreign coins.

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