How many different ways can 2 students be seated in a row of 7 desks, so that there is always at ...
How many different ways can 2 students be seated in a row of 7 desks, so that there is always at least one empty desk between the students?
Answer/Solution
30
Steps/Work
15 ways to seat the students:
with two empty seats between
1 empty w/ one student on the left most
1 empty....right most
two students can be interchanged
15x2=30
C
with two empty seats between
1 empty w/ one student on the left most
1 empty....right most
two students can be interchanged
15x2=30
C