Question

in a flower bed, there are 23 rose plants in the first row, 21 in the second, 19 in the third, and so on. there are 5 rose plants in the last row. how many rows are there in the flower bed?

Answer 1

f(r) = 23 - 2(r - 1)

23 - 2(r - 1) = 5

23 - 2r + 2 = 5

25 - 2r = 5

2r = 20

r = 10 rows