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Paragraph: Let f ( n ) denotes the number of different ways in which the positive integer n can be expressed as the sum of 1 's and 2 's. For example, f(4)=5 , since 4=2+2=2+1+1=1+2+1=1+1+2=1+1+1+1 . Note that order of 1 's and 2 's are important. Question: The value of f(f(6)) is

Options

  1. A400
  2. B350
  3. C377
  4. Dnone of these

Correct answer

C. 377

Step-by-step solution

f(7)=2 13-8+3=21 Similarly f(8)=34, f(9)=55, f(10)=89f(11)=144, f(12)=233, f(13)=377

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