the sum S of the first n natural no. is given by the relation S=n(n

1)/2 find n,if the sum is 55

Given,

S=55,

and S=n(n+1)/2.

Now,

S=n(n+1)/2

55=n² +n/2

55*2=n²+n

110=n²+n

n²+n-110=0

now solve further to get the answer I have given u a hint.OK