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Black and White Socks

Age 14 to 16 Short Challenge Level:


There are 20 black socks and $n$ white socks in a drawer.

A sock is taken from the drawer, and the probability that it is white is $\dfrac{1}{n}$.

What is the value of $n$?



This problem is adapted from the World Mathematics Championships
You can find more short problems, arranged by curriculum topic, in our short problems collection.