A machine in a factory has an error rate of 4 parts per 100. The machine normally runs 24 hours a day and produces 40 parts per hour. Yesterday the machine was shut down for 9 hours for maintenance.

How many error-free parts did it produce yesterday?

In a class of 37 students, 14 are taking German and 13 are taking Spanish. Of the students studying German or Spanish, 4 are taking both courses. How many students are not enrolled in either course?

After being dropped a ball always bounces back to 2/7 of the height of its previous bounce. After the first bounce it reaches a height of 234 inches. How high will it reach on bounce number 5?