Question: In a small town, two landscaping companies fertilize lawns during the summer. Tri-State Lawncare has 72% of the market. Thirty percent of the lawns fertilized by Tri-State could be rated as very healthy one month after they had been fertilized by Tri-State. Greenchem has the rest of the market. Twenty percent of the lawns fertilized by Greenchem could be rated very healthy one month after their service. A lawn that has been fertilized by one of the companies within the last month has been randomly selected. If the lawn is rated as very healthy, what is the probability that the lawn was fertilized by Tri-State?