Which of the following recursive formulas represents the same geometric sequence as the formula an=2*3^(n-1)? When you answer this can you state as well whether its a, b, c, or d? Thank you!

The distribution of a sample of the outside diameters of pvc pipes approximates a symmetrical, bell-shaped distribution. the arithmetic mean is 14.0 inches, and the standard deviation is 0.1 inches. about 68% of the outside diameters lie between what two amounts?