There are 8 periods in each working day of a school. In how many ways can one organize 7 subjects such that each subject is allowed at least one period?
Select.
A) 112456	B) 145678	C) 141120	D) 11456	E) None of these
7 subjects can be arranged in 8 periods in 8P7 ways.   Remaining 1 period can be arranged in 7P1 ways.   Two subjects are alike in each of the arrangement. So we need to divide by 2! to avoid overcounting.   Total number of arrangements = (8P7 x 7P1)/2! = 141120   ANSWER:141120
<result>C</result>
There are 8 periods in each working day of a school. In how many ways can one organize 7 subjects such that each subject is allowed at least one period?