In an A.P. the pp th term is qq and the (p+q)th (p+q)^{\text {th }} term is 0 . Then the qq th term is (A) −p-p (B pp (C) p+qp+q (D) p−qp-q

Answer: The qq th term is pp.

Step-by-step solution

Step 1: Define terms of an A.P.

Let aa be the first term and dd be the common difference of the Arithmetic Progression (A.P.). The nn -th term of an A.P. is given by the formula an=a+(n−1)da_n = a + (n-1)d.

Step 2: Formulate equations from given conditions

According to the problem statement, the pp -th term is qq, so we can write a+(p−1)d=qa + (p-1)d = q. Also, the (p+q)(p+q) -th term is 00, which gives us the equation a+(p+q−1)d=0a + (p+q-1)d = 0. These are our two main equations.

Step 3: Solve for the common difference 'd'

To find the common difference dd, we subtract equation (1) from equation (2). This eliminates aa and allows us to solve for dd. After simplifying, we find that d=−1d = -1.

Step 4: Solve for the first term 'a'

Now that we have the value of dd, we can substitute it back into equation (1) to find the first term aa. Substituting d=−1d = -1 into a+(p−1)d=qa + (p-1)d = q, we get a−p+1=qa - p + 1 = q, which simplifies to a=p+q−1a = p + q - 1.

Step 5: Calculate the q-th term

Finally, we need to find the qq -th term, aqa_q. Using the formula aq=a+(q−1)da_q = a + (q-1)d and substituting the values of aa and dd we found, we get aq=(p+q−1)+(q−1)(−1)a_q = (p+q-1) + (q-1)(-1). This simplifies to p+q−1−q+1p+q-1-q+1, which results in pp.

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