How many different ways can 2 students be seated in a r

[varun289]

How many different ways can 2 students be seated in a row of 4 desks, so that there is always at least one empty desk between the students?
A. 2
B. 3
C. 4
D. 6
E. 12

[nisagl750]

How many different ways can 2 students be seated in a row of 4 desks, so that there is always at least one empty desk between the students?
A. 2
B. 3
C. 4
D. 6
E. 12

Let the two students be A and B

The possible arrangements are
A._.B._
_.A._.B
B._.A._
_.B._.A
A._._.B
B._._.A

IMO D

What is the OA?

[Anurag@Gurome]

How many different ways can 2 students be seated in a row of 4 desks, so that there is always at least one empty desk between the students?

The possible scenarios are,

• 1. They are occupying 1st and 3rd seat
  2. They are occupying 2nd and 4th seat
  3. They are occupying 1st and 4th seat

Hence, 3 ways.

As the two student can be arranged in two ways in each of the above possible scenarios, total number of ways are 2*3 = 6

The correct answer is D.