An employee records the number of prescriptions filled at a pharmacy each hour during an 8-hour period. The table shows the results. The employee spilled coffee on the table, making the entry for hour 2 unreadable. The employee knows that the mean for the data in the table is 21. How many prescriptions were filled during hour 2?

First locate the turning point (vertex) of the graph. which is at the coordinates x=5 and y=9 or (5; 9).to determine whether it's a maximum or mininum value, you have to discern whether the vertex's y-value is the highest value or lowest value the graph can reach. since the vertex's y-value, 9 is the highest value the graph can reach, it will be a maximum.another basic way to determine whether the vertex's value is max or min is to see if the graph is smiling or sad. if it's smiling, the turning point/vertex would be a minimum, while a sad parabola would have a maximum y-value at the vertex.

It'll be 14/21, 8/12, and 10/15.14/21=2/312/16=3/48/12=2/310/15=2/3