... 3, 4, 5, 6 series, and follows each letter inorder.79. d. The second and forth letters in the series,L and A, are static. The first and third let-ters consist of an alphabetical order begin-ning ... repeatsitself, and then increases by 12 to arrive atthe next number. 47 . b. This is an alternating addition and subtrac-tion series, in which the addition of 4 isalternated with the subtraction of 3. 48 . ... with 2 and increases by 2; the secondstarts with 44 and decreases by 3. 45 . a. In this simple subtraction series, the num-bers decrease by 3. 46 . b. In this simple addition with repetitionseries,...