In a flower bed, there are 25 rose plants in the first row, 23 in the second, 21 in the third and so on. There are 3 rose plants in the last row. (i) How many rows are there in the flower bed? (ii) Find the total number of rose plants in the flower bed.
Answers
Answer:
(i)12 (ii) 168
Step-by-step explanation:
1st row 25, 2nd row 23 and so on .. nth row 3
they are in A.P with a=25 and d= -2
We know nth term in A.P is given by
Tn = a+(n-1)d
3= 25 + (n-1)(-2)
2(n-1)=22
n=12
total number of rows = 12
total number of rose plants = sum of A.P
Sum of A.P = (n/2)[2a+(n-1)d]
Here, a=25,d=-2 n=12
total number of rose plants = 6[50-22]
= 6[28]=168
Hope it is helpful
Answer:
(i)12 (ii) 168
Step-by-step explanation:
1st row 25, 2nd row 23 and so on .. nth row 3
they are in A.P with a=25 and d= -2
We know nth term in A.P is given by
Tn = a+(n-1)d
3= 25 + (n-1)(-2)
2(n-1)=22
n=12
total number of rows = 12
total number of rose plants = sum of A.P
Sum of A.P = (n/2)[2a+(n-1)d]
Here, a=25,d=-2 n=12
total number of rose plants = 6[50-22]
= 6[28]=168
Hope it is helpful
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