There are 6 physics books and 1 chemistry book on shelf P and 5 physics books on shelf Q. One book is moved from shelf P to shelf Q. A student picks up a book from shelf Q. What is the probability that the chemistry book is taken by the student?  Select the correct option.
A) 1/42 B) 1/21 C) 1/15 D) 1/12 E) 1/10
P(a chemistry book is moved to shelf Q) = 1/7   P(a chemistry book is then chosen from shelf Q) = 1/6   P(the student takes a chemistry book) = 1/7 * 1/6 = 1/42   The answer is 1/42.
<result>A</result>
There are 6 physics books and 1 chemistry book on shelf P and 5 physics books on shelf Q. One book is moved from shelf P to shelf Q. A student picks up a book from shelf Q. What is the probability that the chemistry book is taken by the student?