A supermarket selected a sample of 240 of its customers and measured how long they took to be served at the checkout counter. If too many customers wait too long, the supermarket intends to hire more checkout personnel. Specifically, the supermarket would like at least 85% of its customers to be checked out in 8.5 minutes or less. From the data, the 90th and 60th percentiles were computed to be 8.6 minutes and 7.1 minutes, respectively. The range of the data was 15 minutes and the fastest anyone was checked out was 1.5 minutes.

Step 3 of 5: Approximately how many customers waited 7.1 minutes or less to be checked out?