If the population of a country increases at a rate of 1.5% annually, and it's current population is 430,000, how many years will it take for the population to triple?

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.