Number series (next term): Two interleaved progressions with increasing gaps. Given sequence: 3, 4, 7, 7, 13, 13, 21, 22, 31, 34, ? Hint: treat odd and even positions separately. Choose the correct next number.

Split sequences

• Odd positions: 3, 7, 13, 21, 31, … differences: +4, +6, +8, +10 ⇒ next odd term = 31 + 12 = 43.
• Even positions: 4, 7, 13, 22, 34, … differences: +3, +6, +9, +12 (multiples of 3).

Next termWe need the 11th term (odd-indexed) ⇒ 43.