tem

In a sequence of 21 terms the first 11 terms are in A.P.with common difference 2. and the lastterms are in G.P.with common ratio 2. If the middle tem of the A.P.is equal to themiddle term of the G.P.,then the middle term of the entire sequence is

The sum of 'n' terms of an A.P is 715.If first term is incrased by 1, second term is increased by 3, third term is increased by 5 and so on k^(th) term is increased by k^(th) odd integer then sum of 'n' tems is 836 then value of (n/6) is

The sum of 20 terms of a series of which every even term is 2 xx the term before it,every odd term is 3 xx the term before it,the first tem being unity is ((2)/(7))(6^(10)-1) b.((3)/(7))(6^(10)-1) c.((3)/(5))(6^(10)-1) d.none of these