If n is negative, all but which of the following must also be negative ? ?
a) n5, b) n3, c) 1/n, d) 1/n2, e) 1/n3

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.