Choose the correct choice in the following and justify:- (ii)11th term of the A.P. -3, -1/2, ,2 …. is (A) 28 (B) 22 (C) – 38

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This question is from Ncert Book class 10th Ch. no.5 Ex. 5.2 Q. 2 (ii) . In the following question you have to find the right option & justify your answer by giving the solution. This question uses fundamental idea of A.P.

Solution:A.P. = -3, -1/2, ,2 …

So, we can find,

1st value,

a= – 3C.D ,

d=a_{2}−a_{1}= (-1/2) -(-3)=(-1/2) + 3 = 5/2

For an A.P we know:_

a=_{n}a+(n−1)dPutting down the above values:-

a_{11}= 3 + (11 – 1)(5/2)a_{11}= 3 + (10)(5/2)a_{11}= -3 + 25a_{11}= 22So, the answer of the above series is B.