Manoj deposited 29400 Rs. for 6 years at a simple interest. He got 4200 Rs. as interest after 6 years. The annual rate of interest was :

Manoj deposited 29400 Rs. for 6 years at a simple interest. He got 4200 Rs. as interest after 6 years. The annual rate of interest was :
[A]2\frac{8}{21}\%
[B]2\frac{7}{20}\%
[C]3\frac{8}{21}\%
[D]4\frac{8}{21}\%

\mathbf{2\frac{8}{21}\%}
4200 = \frac{29400\times 6\times R}{100}
=> R = \frac{4200}{294\times 6} = \frac{50}{21} = 2\frac{8}{21}\%
Hence option [A] is correct answer.