if i get an 11/40 on a semester exam and the exams are 10% of your grade and i have an 80% in that class, how much would that bring down my grade?

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.