The successive terms of an A.P.are `a_(1),a_(2),a_(3),...` .If `a_(6)+a_(9)+a_(12)+a_(15)=20,` then `sum_(r=1)^(20)a_(r)`

The sum of 19 terms for AP. a_(1),a_(2),....a_(19) & given a_(4)+a_(8)+a_(12)+a_(16)=224, is

If the sum of first 11 terms of an A.P., a_(1),a_(2),a_(3),.... is 0(a_(1)!=0) then the sum of the A.P., a_(1), a_(3),a_(5), ......,a_(23) is k a_(1) , where k is equal to :

Find the sum of first 24 terms of the A.P. a_(1) , a_(2), a_(3) ...., if it is know that a_(1) + a_(5) + a_(10) + a_(15) + a_(20) + a_(24) = 225

Find the sum of first 24 terms of the A.P.a_(1),a_(2),a_(3),..., if it is know that a_(1)+a_(5)+a_(10)+a_(15)+a_(20)+a_(24)=225

(i) Find the sum of first 24 terms of the A.P.a_(1),a_(2),a_(3),...... if it is know that a_(1)+a_(5)+a_(10)+a_(15)+a_(20)+a_(24)=225

For an increasing G.P. a_(1), a_(2), a_(3),.....a_(n), " If " a_(6) = 4a_(4), a_(9) - a_(7) = 192 , then the value of sum_(l=1)^(oo) (1)/(a_(i)) is

For an increasing geometric sequence a_(1),a_(2),a_(3),...,a_(n) if a_(6)=4a_(4) & a_(0)-a_(7)-192 and sum_(1=4)^(n)a_(i)=1016 ,then n is