Question

39) The sum of first n natural numbers is given by the
expression 1/2 n2 + 1/2 n. What is the sum of natural
numbers starting from 9 and ending with 20, inclusive of
both 9 and 20?
A) 144
B) 156
C) 174
D) 192​

Answer 1

Answer:

Rishabh Raj

Step-by-step explanation:

the sum of first natural number is 2 by 1 one by two x degree by answer is d