For C, the answer is x = 20. Explanation: the sum of the two angles is equal to 180 degrees, since they are across parallel lines. Plug the two angles into an equation that equals 180. You should have (2x + 20) + 120 = 180. Simplify the equation by subtracting 120 from both sides. You should now have 2x + 20 = 60. Subtract 20 from both sides. 2x = 40. Now simplify the equation by dividing both sides by 2, and you get your answer, x = 20. The answer for D is x = 30. Explanation: Since the angles are on the same side of parallel lines, they are equal. Plug the angles into an equal equation: 3x + 10 = 100. Subtract 10 from both sides to get 3x = 90. Now divide both sides by 3 to get your answer, x = 30.
The answer you seek you just need to take 325 and divide it by 500 to get .65 and change .65 to 65%. And to make sure you multiply 500 by .65 to get 325. Hope I helped