1) Fisherâ??s Index is G.M. of Laspeyresâ?? and Paascheâ??s Index Number (Fisherâ??s Index is Ideal Index )
2) Bowleyâ??s Index is the A.M. of Laspeyresâ?? and Paascheâ??s Index Number
By using the above two you can get the answer.
OR
F^2=LÃ?P & 2B=L+P