There are 5 periods in each working day of a school. In how many ways can one organize 4 subjects such that each subject is allowed at least one period?  Choose the correct choice from the following answers
A) 240
B) 250
C) 260
D) 280
E) None of these
4 subjects can be arranged in 5 periods in 5P4 ways.   Remaining 1 period can be arranged in 4P1 ways.   Two subjects are alike in each of the arrangement. So we need to divide by 2! to avoid overcounting.   Total number of arrangements = (5P4 x 4P1)/2! = 240   240NSWER:240
<result>A</result>
There are 5 periods in each working day of a school. In how many ways can one organize 4 subjects such that each subject is allowed at least one period?