Is the sequence 2, 4, 6, 8... a geometric progression?

Find the sum of the first 10 numbers of this arithmetic series: 1, 11, 21, 31...

Is the sequence 2, 4, 6, 8... a geometric progression?

Find the scale factor and the command ratio of a geometric progression if a5 - a1 = 15a4 - a2 = 6

in an arithmetic progression, the sum of the 1st 3 terms is 18, and the sum of the squares of these terms is 126. find the terms. how is the solution? 

 Which term of the A.P. 3,8,13 …is 78?

Find the 10th term of -5,-8,-11,......[A] -28[C] -32[B] -18[D] -20

Find the 32nd term in the following series 3,7,11,.......[A] 120[C] 220[B] 230[D] 127

Find the values of x in the Arithmetic series 3x+1,5x-1,5x+1,......[A] 2[C] 8[B] 3[D] 7