Question

plz, tell me the answer of the question given in the picture

Answer 1

Hello Friend,

Here's the solution.

In the solution,
you need to know that:

1 + 2 + 3 + ... + n = n(n+1)/2

(It is an A.P. and it's sum can be found, in case you don't know the direct formula)

The rest of the solution is shown.
Your answer is Option (b).


Hope it helps.

Purva
@Purvaparmar1405
Brainly.in