Given,
Rooms are identical,
So, total ways to distribute 5 employees into 4 rooms are:
5,0,0,0⇒1 way
4,1,0,0⇒4!5!=5 ways
3,2,0,0⇒3!2!5!=10 ways
2,2,0,1⇒2!2!2!5!=15 ways
2,1,1,1⇒2!(1!)33!5!=10 ways
3,1,1,0⇒3!2!5!=10 ways
Total ⇒1+5+10+15+10+10=51 ways