1. A supermarket display consists of boxes of cereal. The bottom row has 23 boxes. Each row has three fewer boxes than the row below it. The display has six rows.
(a) Write and use a function to determine how many boxes are in the top row. Show your work.
(b) Use the appropriate formula to determine the number of boxes in the entire display. Show your work.
a) To find the number of boxes in any row...we can use
an = 23 - 3 (n - 1) where n is an integer from 1 to 6 inclusive
So...in the 6th row, we have
a6 = 23 - 3(6 - 1) = 23 - 3(5) = 23 - 15 = 8 boxes
b) To find the total number of boxes, we can use
[ Number of boxes in the first row + Number of boxes in last row ] * [ No. of rows / 2 ]
So we have
[ 23 + 8 ] * [6/2] =
 *  =
93 boxes in total