Hard
Find the next number in the series: 15, 24, 33, 42, ?
Explanation
Explanation
Each term increases by a constant difference of 9 (i.e. 24-15=9, 33-24=9, and so on). Continuing the pattern, the next term = 42 + 9 = 51.
PRO TIP
Re-check your working by substituting the answer back into the original question.