The reflector of a flashlight is in the shape of a parabolic surface. The casting has a diameter of 8 inches and a depth of 3 inches. How far from the vertex should the light bulb be placed

Lizette is training for a marathon. at 7: 00 she left her house and ran until 8: 30, then she walked until 11: 30. she covered a total distance of 18 miles. her running speed was six miles per hour faster than her walking speed. find her running and walking speeds in miles per hour.