Lisa rents a phone from t-mobile. each month she pays $25 and an additional $.075 per text. let b represent the money she gets billed and t represent the number of texts sent.

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.