On a typical day, the Stonebriar mall sees customers arriving at an average rate of 225 per hour. Each customer stays in the mall for an average of 135 minutes. 1. What is the average number of customers in the mall at any time? A third of all the customers come alone and make up, on average, 20% of the customers in the mall. The remaining customers come to mall with their families. 2. How long, on average, does a single customer (those who come alone) spend in the mall? 3. Estimate the average time a typical family spends in the mall.