If a sequence of 8 consecutive odd integers with increasing values has 9 as the 7th term what is the sum of the terms in the sequence?
thanks!
thanks!
If a sequence of 8 consecutive odd integers with increasing values has 9 as the 7th term what is the sum of the terms in the sequence?
thanks!
soln:
we know number of the form 2n+1 is odd
funda out here will be to choose odd number in such a way that it helps in solving:
2n-1 ,2n-3,2n-5 (subtracting 2 from 2n+1 will result in odd number)
2n+3,2n+5, will be odd
so 8 consecutive odd numbers will be 2n-7,2n-5,2n-3,2n-1,2n+1,2n+3,2n+5,2n+7
now 7th term is 2n+5 ie given as 9
2n+5=9 solving we get n as 2
replacing n=2 n series we will get
series =-3,-1,1,3,5,7,9,11
sum=32
now
