A cleaning company uses a cleansing chemical and odor-removing chemical to clean a house. Each unit of the cleansing chemical takes 4 units to be effective while each unit of the odor-removing chemical takes 6 minutes to be effective. The company must use at least 100 units of the cleansing chemical. In total, at least 300 units of chemicals can be used per house. Further, because the cleansing chemical is strong, there can be at most twice the amount of cleansing chemical as odor-removing chemical. How many units of each should be used to minimize the total time it takes for a house to be cleaned?