The human resource department at a certain company wants to conduct a survey regarding worker benefits. The department has an alphabetical list of all 7148 employees at the company and wants to conduct a systematic sample of size 70.

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.