A) Rs. 10000
B) Rs. 6000
C) Rs. 12000
D) Rs. 8000
E) None of these
Correct Answer: D
$ \Rightarrow $ $ x{{( \frac{21}{20} )}^{4}}-x-\frac{x}{5}=124.05 $
$ \Rightarrow $ $ x( \frac{441\times 441}{16\times 10^{4}} )-\frac{6x}{5}=124.05 $
$ \Rightarrow $ $ x( \frac{194481-192000}{160000} )=124.05 $
$ \Rightarrow $ $ x=\frac{124.05\times 160000}{2481} $
$ \Rightarrow $ $ x=Rs.,8000 $