Both fertilizer and seeds need to be added to a lawn. One unit of fertilizer takes 0.5 minutes to be effective while one unit of seeds takes 1.5 minutes to be effective. There can be at most 300 units of fertilizer and seeds combined added to the lawn. In addition at least 50 units of fertilizer need to be added. Since the lawn is really patchy, there can be at most twice the amount of fertilizer as seeds. How many units of each should be added to minimize the total time it takes for the lawn to be ready?