Explain the steps needed to determine the value of the ex below. be sure to provide the correct value of the expression in your explanation. 1/2 —— -2/5. + ( -1/4)

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.