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+2 votes

If the ratio of the sums of first p terms and q terms of an AP is p^2 : q^2 , then the ratio of its pth and qth terms is :

a. (2p-1) : (2q-1)

b. (2p+1) : (2q+1)

c. p : q

d. (p+1) : (q+1)

a. (2p-1) : (2q-1)

b. (2p+1) : (2q+1)

c. p : q

d. (p+1) : (q+1)

0 votes

We can also solve it like this :

We know nth term of AP t_{n} = S_{n} - S_{n-1} ( where S_{n} means sum of n terms)

So if sum of p terms = p^{2} (say)

sum of (p-1) terms = (p-1)^{2}

Hence , pth term can be written as : p^{2} - (p-1)^{2} = 2p - 1

Similarly qth term can be written as : q^{2 }- (q-1)^{2} = 2q -1

Hence the ratio of pth and qth term : (2p-1) / (2q-1)

Hence the correct option is A)

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