Question

2. A supermarket display consists of boxes of cereal. The bottom row has 27 boxes. Each row has four 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.
(b) Use the appropriate formula to determine the number of boxes in the entire display.

Answer 1

Explanation:

) Nth term = F + (N - 1) x D, where F=First term, N=Number of terms, D=Common difference

6th row = 23 + (6 - 1) x -3

= 23 + (5) x -3

= 23 + (-15)

= 8 - number of boxes in the top row.

b) Sum = N/2[2F + (N - 1) x D]

= 6/2[2*23 + (6 - 1) x -3]

= 3 [46 + (5) x -3 ]

= 3 [46 + -15 ]

= 3 [ 31 ]

= 93 - total number of boxes in the entire display.