For each month of a given year except December, a worker earned the same monthly salary and donated one-tenth of that salary to charity. In December, the worker earned N times his usual monthly salary and donated one-fifth of his earnings to charity. If the worker's charitable contributions totaled one-sixth of his earnings for the entire year, what is the value of N? Choose the correct choice from the following choices:
A) 8/5  B) 22  C) 3  D) 11/3  E) 4
Let monthly salary for each of the 11 months except December was x, then   11x*1/10 + Nx*1/5 = 1/6(11x + Nx);   11/10 + N/5 = 1/6(11 + N)   11+2N/10 = 11+N/6 =&gt;66+12N = 110+10N =&gt;2N=44   N = 22   Answer: 22
<result>B</result>
For each month of a given year except December, a worker earned the same monthly salary and donated one-tenth of that salary to charity. In December, the worker earned N times his usual monthly salary and donated one-fifth of his earnings to charity. If the worker's charitable contributions totaled one-sixth of his earnings for the entire year, what is the value of N?