Question

The sum of fist n natural numbers is given by 1/2(n2+n) . Find:- The sum of natural numbers from 11to 30.​

Answer 1

Answer:

210

Step-by-step explanation:

11 to 30 means n=20

Now,substitute the value of n in 1/2(n²+n)=1/2((20)²+20)

=1/2(400+20)

=1/2(420)

=210