Question

60. In a flower bed, there are 23 rose pants in the first row, 21 in the second, 19 in the third and so
was found to be 4°C per minute. Calculate the time
sea level by using formula.
There are 5 rose plants in the last row. How many rows are there in the flower bed?​

Answer 1

Answer:

The number of rose plants in first, second third,..., and last row are respectively.

23,21,19,....,5.

Let the number of rows of rose plants n.

The sequence 23,21,19,....,5 is an A.P. with first term a(=23), common difference d(=−2) and n

th

term (=5).

∴a

n

=a+(n−1)d

⟹5=23+(n−1)×−2

⟹5=23−2n+2⟹20=2n⟹n=10

Hence, there are 10 rows of rose plants.