In a flower bed there are 25 rose plants in the first row, 22 in the second , 19 in the third and so on. there are 4 rose plants in the last row. how many are there in the flower bed?
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Answered by
3
These are in sequence of A.P=25,22,19,........,4
Then a=25
d=22-25=-3
L=4
L=a + (n – 1) d
4=25+(n-1)-3
4=25-3n+3
4=28-3n
3n+4=28
3n=28-4
3n=24
n=24/3
n=8
There fore there are 8 bedroses.
Then a=25
d=22-25=-3
L=4
L=a + (n – 1) d
4=25+(n-1)-3
4=25-3n+3
4=28-3n
3n+4=28
3n=28-4
3n=24
n=24/3
n=8
There fore there are 8 bedroses.
timmy:
thanks... :)
tq so much dr
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Answered by
2
a=25
d= -3
an = 4
n= ?!
an=a+(n-1)d
4=25-3n+3
4=28-3n
-24= -3n
n= -24/-3
n = 8
There are 8 rows
d= -3
an = 4
n= ?!
an=a+(n-1)d
4=25-3n+3
4=28-3n
-24= -3n
n= -24/-3
n = 8
There are 8 rows
thanks...
:) :D
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