1) IF A SERIES OF TERMS IN ARTHMETIC PROGRESSION BE COLLECTED INTO GROUPS OF N TERMS AND THE TERMS IN EACH GROUP BE ADDED TOGETHER, THEN THE RESULT FORMS AN ARTHEMETIC PROGRESSION, THEN THE RATIO OF THE COMMON DIFFERENCE OF THAT ARTHEMETIC PROGRESSION TO THE ORGINAL COMMON DIFFERENCE.

(A)n² :1 (B)n² +1:1 (C)n² -1:1 (D) n-1:n+1

Dear dilip

let first term is a and common difference is d

so first term of new series   = n/2[2a +(n-1)d]

and second term of new series =2n/2[2a +(2n-1)d] -n/2[2a +(n-1)d]

so common difference of new series  d' =2n/2[2a +(2n-1)d] -n/2[2a +(n-1)d] -n/2[2a +(n-1)d]

                                                         =2n/2[2a +(2n-1)d -n[2a +(n-1)d]

  or d'/d =n²/1

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