Chapter 5 Progressions

Question

a) Supermarket A displays the can drink in the form of a pyramid. 41 cans in the bottom-most row, 37 cans in the next row, followed by 33 cans and so on for the rows above the rows.

i) the number of cans at the 8th row.

ii) How many rows are there, if there is 25 cans on the topmost row?

iii) If the process carried on, determine

a) the number of possible rows,

b) the number of cans on the topmost row

Answer 1

a_n = 41 + (n - 1)(-4)

a₈ = 41 + 7(-4)

25 = 41 + (n - 1)(-4)

0 = 41 + (n - 1)(-4)