The common difference of the AP `1/p,(1-p)/p,(1-2p)/p..........`is

The sum of the first ten terms of an A.P. , equals 155 and the sum of the first two terms of a G.P. equals 9. The first term of the A.P. is equal to the common ratio of the G.P. and the common difference of the A.P. is equal to the first term G.P.. Give that the common difference of the A.P. is less then unity, which of the following is correct ?

If a ,1/b ,c and 1/p ,q ,1/r form two arithmetic progressions of the common difference, then a ,q ,c are in A.P. if p ,b ,r are in A.P. b. 1/p ,1/b ,1/r are in A.P. c. p ,b ,r are in G.P. d. none of these

Write the common difference of an A.P. the sum of whose first \ \ n terms is P/2n^2+Q n

If the values of x between 0 and 2 pi which satisfy the equation "sin" x|"cos"x| = (1)/(2sqrt(2)) are in A.P, then the common difference of the A.P, is