Question

10. The range of the first 20 odd natural numbers is
а) 39
b) 19

С) 40
d) 38​

Answer 1

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:

2

n

(2a+(n−1)d)

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

Substituting these, we get

Sum of first 20 natural numbers:

2

20

(2(1)+(20−1)2)

=10×(2+19×2)=10×40=400

Answer 2

Answer:

The first 20 odd natural numbers are given by : 1,3,5,7,9......,37,39. Put all the values in the formula, Therefore,The sum of first 20 odd natural numbers is 400.

Step-by-step explanation:

Formula is n2 = 20 X 20 = 400