At the candy shop you see some tasty-looking gumdrops, jellybeans, and mints, each in yellow, blue, and white.
You buy 10 of each kind (90 candies altogether), take them home, and dump them in a bowl.
After an hour of solitary nibbling, the total of yellow gumdrops, blue gumdrops, yellow jellybeans, and blue jellybeans is down to nine.
The bowl contains only half as many yellow candies as gumdrops, half as many mints as white candies, and half as many blue candies as jellybeans.
How many white mints have you eaten?
(Show your work or give an explanation)