13.63 * 38 = 517.94
671.28 - 517.94 = 153.88
153.88 : 13.63 = 11.25 the number of hours she overworked
1 serving = 2/3 cup
12 serving = 2/3 x 12 = 8 cups
Answer: 12 servings of muffin would need <u>8 cups</u> of the muffin mix.
Angle 8 because supplementary is two angles whose sum is 180°.