Multiple choice general knowledge math & puzzles

What is the missing number in the series? 4,9,20,43,90??

  1. 170

  2. 185

  3. 209

  4. 222
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The pattern is (n * 2) + 1, then (n * 2) + 2, then (n * 2) + 3, etc. 4*2+1=9; 9*2+2=20; 20*2+3=43; 43*2+4=90. The next step is 90*2+5 = 185. 170 and 222 do not follow this incremental multiplier-addition rule.

Keep practicing — related questions