Q. 30

Which term of the

Answer :

Given AP is


Whose, first term, a = 20


common difference,



Let nth term of the AP be the first negative term.


Then, we have to find the least value for which


an < 0


And we know, nth term of an AP = a + (n - 1)d


Where a and d are first term and common difference respectively.


a + ( n - 1 )d < 0




-3( n - 1 ) < -80


3(n - 1) > 80


3n - 3 > 80


3n = 83



so, n will be least natural number greater than i.e.


i.e., 28th term is the first negative term of the given AP.

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