Question

Find the three arithmetic means between 5 and 17.

Answer 1

Inserting 3 arithmetic means between 5 and 17 makes an arithmetic sequence with 5 as the first term and 17 as the fifth term. Solve for the common difference by,
                                    d = (a5 - a1) / (5 - 1)
                                     d = (17 - 5) / (5 - 1) = 3
Then the terms are calculated by the equation,
                                    an = a1 + (n - 1) x d
From this, the value of the arithmetic means are 8, 11, and 14.