2x = 8 ... therefore x = 4
4^2 = 16
360/20 is equal to 18 sides
In 10 minutes, Tom eats (5 cookies/minute)×(10 minutes) = 50 cookies.
Andy must eat the remaining cookies:
... 80 cookies - 50 cookies = 30 cookies.
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The answer to the question asked is
Andy must eat 30 cookies.
The answer to the question not asked is
Andy eats those cookies at the rate
... (30 cookies)/(10 minutes) = 3 cookies/minute