Answers

2014-12-14T22:44:22+05:30
We have a=22 and d=4
   Sn= n[(2a+( n-1)d]/2
⇒ 64=n(44+4n-4)/2
⇒128= 40n-4n²
⇒ n²-10n + 32=0
solving the quadratic equation we have 
n=+_5+_√-28
This is not correct value for n. I think the sum to N term can not be 64 as the terms are 22,26,30 hence we can not get Sn=64 .
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