Question

In an A.P the 12th term is -13 and the sum of first four term is 24. What is the sum of the first 10 terms?

Answer 1

Hey there!!!



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A12=a+11d
-13=a+11d

S4=n/2(2a+(n-1)d)

So,

12=2a+3d

Therefore,

12=2(-13-11d)+3d
12=-26-22d+3therefore,


D=-2

And keeping it in above
A=9

So using sum to 10terms.


S10=n\2(2a+(n-1)d


S10=0


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Hope it helps you!!

Thanks!!

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