What is the next number in the sequence 3, 8, 18, 38, 78, ...?
Answer and explanation
Correct answer: D. 158
- Step 1: Look at how each term is made: 3 x 2 + 2 = 8, 8 x 2 + 2 = 18, 18 x 2 + 2 = 38, 38 x 2 + 2 = 78.
- Step 2: The next term is 78 x 2 + 2 = 158.
Answer
158.
Why not the others: 118 adds 40 as if the gap stayed constant, 156 forgets the +2 and 154 adds 76.
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