Number Series Puzzles Questions

19. What number should replace the question mark?
  What is the next number?
Answer
Ans = 6.
The total of the numbers in each column alternates 20, 30, 20, 30, 20, 30.
20. What number should replace the question mark?
  What is the next number?
Answer
Ans = 72.5.
The amount deducted increases by 2.75 each time i.e. 2.75, 5.5, 8.25, 11.
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