Michael wants to purchase a precision balance for $340. He has already saved $113 and can save $28 every week. Write an inequality that can be used to determine the number of weeks left for Michael to save at least $340.
Michael finds two plumbers online: the first charges $20 per hour of labor, while the second charges a fixed charge of $40 per job plus an hourly labor charge of $15. After how many hours will the second plumber be cheaper than the first?
Sophia finds two landscape gardeners online: the first charges a fixed fee of $20 per job plus $15 per hour for labor, while the second charges a fixed fee of $90 but only $5 per hour for labor. After how many hours will the second gardener be cheaper than the first?