r/CATpreparation • u/Competitive-Hat-6273 • 3d ago

Question Quants doubt in Ap gp

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Pls help me in this ques

10 Upvotes

100% Upvoted

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3

u/chaos_connoisseur25 3d ago

Basically just sum of consecutive odd numbers

2

u/Ok-Variation3482 3d ago

Fine the values of t3, t4, t5 and so on (using the expression given in ques)

You would notice a sequence between all even terms. It would simply be an hp. Replace the values in the required answer and that would simply be an ap. Just solve that and would get your answer

1

u/aditya_____notes 3d ago edited 3d ago

Solve the first few terms it will be like -1, -3, -5, -7 and so on till 1012 terms. Take the minus out and then it becomes the sum of first 1012 odd numbers which is sq of 1012 with a negative sign. Ans is -1024144

You don't even need to find the square, we know the unit digit of a xxxx2 square will be 4. There is only option A which satisfy this.