A) \[72Hz\]
B) \[288Hz\]
C) \[84Hz\]
D) \[87Hz\]
Correct Answer: C
Solution :
If n is the frequency of last fork then frequency of first fork be\[2n\]. So, \[2n-(25-1)\times 3=n\] \[\Rightarrow \] \[n=72Hz\] 21st fork frequency\[=144-(21-1)(3)=84\,\,Hz\]You need to login to perform this action.
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