alleryStart learning →Which term completes 4, 9, 19, 39 in the same rule?
A78
B80
C81
D79
Answer & Solution
Correct answer: D. 79
Each term is double the previous plus 1 (4x2+1=9, 9x2+1=19, 19x2+1=39), so 39x2+1 = 79.
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