Question

find the sum of 1st 20 term odd number​

Answer 1

Answer:

refer the below step by step answer

Step-by-step explanation:

First 20 odd natural numbers:

First term,  a=1

Common difference, d=2

Sum of first n terms of and AP:    n/2(2a+(n−1)d)

Here, n=20,a=1,d=2

Substituting these, we get

Sum of first 20 natural numbers: 20/2 (2(1)+(20−1)2)

=10×(2+19×2)

=10×40

=400