Find the three arithmetic means between ­4 and 16.

7, 10 and 13.

Step-by-step explanation:

If there are 3  means between 4 and 16 then:

16 is obtained by  adding the common difference 4 times:

(16 - 4)/4 = 12/4 = 3 = common difference.

So the 3 arithmetic means are 4+3, 4 +2*3, 4 + 3(3)

That is 7, 10 and 13.

the mistake in the pattern is that :

b. the decimal point was moved one too many place values each time

the correct pattern could be made by :

b. moving the decimal point to the right the same numbers of place values as the exponents