Medium
Find the missing number in the series: 41, 31, ?, 17, 11, 5
Explanation
Explanation
The gaps between terms are 10, 8, 6, 6, 6 (decreasing by 2 for the first two steps, then staying constant). So 31 - 8 = 23, and 23 - 6 = 17, which matches the next given term. The missing number is 23.
PRO TIP
Re-check your working by substituting the answer back into the original question.