Question

What is the sum of odd numbers from 1 to 40​

Answer 1

Answer:

so there are 20 odd number between 1 to 40

Answer 2

Answer:

1. we know, Tn=2n-1=39
2. so we get. n=20
3. we know the formula of sum, Sn=n/2{2a+(n-1)d}
4. put the value
5. 20/2{2*1+(20-1)2}=10{2+38}=400