If `18 ,\ a ,\ b ,\ -3` are in A.P., the `a+b=` (a) 19 (b) 7 (c) 11 (d) 15

If 18,a,b,-3 are in AP,then a+b=

State 'T' for true and 'F' for false . I. A sequence is an A.P ., if and only if the sum of its n terms is of the form An^(2) +Bn , where A and B are constants . II. If 18, a, b , -3 are in A.P., then a+b = 15 . III If a,c,b are in A.P., then 2c=a+b . IV .The n^(th) term from the end of an A.P. is the (m-n+1)^(th) term from the beginning , where m terms are in A.P.

Let a,b,c are 7^(th), 11^(th) and 13^(th) terms of constant A.P if a,b,c are also is G.P then find (a)/(c ) (a) 1 (b) 2 (c) 3 (d) 4

If a, b, c, d, e, f are in A.P., then e – c is equal to

The number of terms of the A.P. 3,\ 7,\ 11 ,\ 15 ,\ ddot to be taken so that the sum is 406 is (a) 5 (b) 10 (c) 12 (d) 14

If a,b,c, are in G.P. , a.x.b in A.P. and b,y,c in A.P., then : (a)/(x)+( c )/(y) = (A) 1/2 (B) 1 (C) 2 (D) none of these

3, 7, 6, 5, 9, 3, 12, 1, 15, (......) (a) 18 (b) 13 (c) -1 (d) 3