Question 12
What is the next number in the series?
$16\quad21\quad12\quad18\quad10\quad17\quad8\quad\underline{\qquad}$
Pattern note (editorial): use the intended pattern of the increase within consecutive pairs of terms.
$16\quad21\quad12\quad18\quad10\quad17\quad8\quad\underline{\qquad}$
Pattern note (editorial): use the intended pattern of the increase within consecutive pairs of terms.