a) To find the number of boxes in any row...we can use
an = 63 - 7 (n - 1) where n is an integer from 1 to 6 inclusive
So...in the 6th row, we have
a6 = 63 - 7(6 - 1) = 28 boxes
b) To find the total number of boxes, we can use
Sum =
[ Number of boxes in the first row + Number of boxes in last row ] * [ No. of rows / 2 ]
So we have
[ 63 + 28 ] * [6/2] =
273 boxes in total
Used answer by CPhill for framework: https://web2.0calc.com/questions/anyone_11
-Vinculum