Question

Sum of first ‘n' natural numbers is 231. What number is ‘n'?

Answer 1

Answer:

I think this question id half

Answer 2

Step-by-step explanation:

S=

2

n(n+1)

⇒231=

2

n(n+1)

⇒n

2

+n−462=0

⇒n

2

+22n−21n−462=0

⇒n(n+22)−21(n+22)=0

⇒(n+22)(n−21)=0

⇒n=−22 or n=21

∴n=21 as n=−22 is not a natural number.