SOLUTION: Karen collects local and foreign coins. Of the coins in her collection, 1/4 are foreign. Of the foreign coins, 2/5 are from Mexico. What fraction of the collection are foreign coi

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Question 1062672: Karen collects local and foreign coins. Of the coins in her collection, 1/4 are foreign. Of the foreign coins, 2/5 are from Mexico.
What fraction of the collection are foreign coins that are not from Mexico?
1/4*2/5=2/20=1/10 from Mexico
9/10 not from Mexico.

Found 2 solutions by math_helper, MathTherapy:
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!

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.

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

Check: (3/20)C + (2/20)C = (5/20)C = (1/4)C = F = number of foreign coins.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

Karen collects local and foreign coins. Of the coins in her collection, 1/4 are foreign. Of the foreign coins, 2/5 are from Mexico.
What fraction of the collection are foreign coins that are not from Mexico?
1/4*2/5=2/20=1/10 from Mexico
9/10 not from Mexico.
Fraction of foreign coins that are from Mexico: matrix%281%2C3%2C+2%2F5%2C+of%2C+1%2F4%29
Fraction of foreign coins that are NOT from Mexico: highlight_green%28matrix%281%2C5%2C+3%2F5%2C+of%2C+1%2F4%2C+or%2C+3%2F20%29%29