Question:
5, 11, 21, 43, 85, ?
5, 11, 21, 43, 85, ?
Show Hint
Look for alternating \(\pm 1\) after a common multiplier.
Updated On: Mar 23, 2026
- 185
- 170
- 171
- 181
Show Solution
Verified By Collegedunia
The Correct Option is C
Solution and Explanation
The pattern doubles and alternately adds/subtracts 1:
\[
5\!\times\!2{+}1=11,\quad 11\!\times\!2{-}1=21,\quad 21\!\times\!2{+}1=43,\quad 43\!\times\!2{-}1=85.
\]
Next:
\[
85\!\times\!2{+}1=171.
\]
\[
\boxed{171}
\]
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