Multiple choice

Find the missing number (?) in the series. $3, 7, 13, 21, 31, ?$

  1. $41$
  2. $42$
  3. $43$
  4. $44$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Calculate the differences: 7-3=4, 13-7=6, 21-13=8, 31-21=10. The differences increase by 2 each time (4,6,8,10). Following this pattern, the next difference should be 12. So 31+12 = 43. Option C is correct.

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