Step 1: Separate the sequence into two interleaved sub-sequences by position. Odd positions (1st, 3rd, 5th, 7th, 9th): 3, 5, 7, 9, ___ Even positions (2nd, 4th, 6th, 8th): 7, 13, 19, 25 Step 2: Find the rule for each sub-sequence. Odd-position sub-sequence: 3, 5, 7, 9 — common difference = 2. Even-position sub-sequence: 7, 13, 19, 25 — common difference = 6. Step 3: Identify the position of the blank. The sequence has 8 terms shown, so the blank is the 9th term. Position 9 is odd. Step 4: Apply the odd-position rule. The 4th odd-position term is 9; the 5th is 9 + 2 = 11. Answer: 11