1. The problem asks: How many customers queued for more than 20 minutes? 2. From the cumulative frequency graph, find the total number of customers who queued up to 20 minutes. The cumulative frequency at 20 minutes is approximately 90 customers. 3. The total number of customers is 100 (the maximum cumulative frequency). 4. To find the number of customers who queued for more than 20 minutes, subtract the cumulative frequency at 20 minutes from the total number of customers: $$100 - 90 = 10$$ 5. Therefore, 10 customers queued for more than 20 minutes.