Question

Question 5. In a Flower bed there are tweenty three rose plants in the first row, tweenty one in the second, nineteenth in the third and so on. There are five plants in the last row. How many rows are there of rose plants.

Answer 1

Step-by-step explanation:

$\huge\underline\mathbb\red{GIVEN}$

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

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

$\sf\large\underline\purple{let-:}$

$\rm{\implies the \:number\: of\: rows\: of\: rose\: plants \:n.</p><p></p><p> }$

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

$\sf\large\green{∴an=a+(n−1)d</p><p>}$

⟹5=23+(n−1)×−2

⟹5=23−2n+2

⟹20=2n

✅⟹n=10

HOPE I HELPED.....! :D

Answer 2

$\huge\underline\mathbb\red{GIVEN}$

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

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

$\sf\large\underline\purple{let-:} </p><p>$

$\rm{\implies the \:number\: of\: rows\: of\: rose\: plants \:n. }$

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

$\sf\large\green{∴an=a+(n−1)d }$

⟹5=23+(n−1)×−2

5=23+(n−1)×−2⟹5=23−2n+2

5=23+(n−1)×−2⟹5=23−2n+2⟹20=2n

5=23+(n−1)×−2⟹5=23−2n+2⟹20=2n✅⟹n=10

HOPE I HELPED.....! :D