In this data sufficiency question, the following is asked: "If each of the 20 bolts of fabric on a shelf is either 100 percent cotton, 100 percent wool, or a mixture of cotton and wool, how many bolts are cotton and wool mixtures?"
(1) Of the 20 bolts, 18 contain some wool and 14 contain some cotton.
(2) Of the 20 bolts, 6 are 100 percent wool.
The correct answer is A. In the solution, the first statement is sufficient because: (14 - n) + n + (18 - n) = 20. The "n" is defined as the number of bolts that are cotton and wool mixtures. Can you explain this part in detail, please? Specifically, I don't know how "some wool" and "some cotton" from statement one are translated into the equation above.