Oh ok. I do have a question though: Say I have two arrays where the first array contains the number of "tutoring sessions" and the second array contains the "lesson duration":
Array ( => 2  => 3 )
Array ( => 45  => 90 )
and what I want to do is multiply the matching keys between the two. For example, key of  is in both arrays and i want to multiply 2 * 45 and 3 * 90.
In addition do that I want to take those results and add them together to get total minutes (in this example, it is 90 + 270 = 360). From there I would take the result and say like "Total lesson minutes: 360"