Each interior angle of a regular n-sided polygon is 150 degrees. How many sides does the polygon have?

The sum of the interior angles of the polygon = (n - 2) x 180.

(n - 2) x 180 = (n x 150)

180n - 360 = 150n

Add 360 to each side:

180n = 150n + 360

Subtract 150n from each side:

30n = 360

Divide each side by 30:

n = 12