How many different ways can 2 students be seated in a row of

Question

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?

nakib77 · Answer

I got 6 by manually arranging 2 students in 4 rows

let x and y be the student

so possible seating arrangemtns are:

x . y .
x . . y
. x . y
y. x . 
y. . x
. y. x

there can not be any other sitting arrangements.

so 6 is the answer.

tank · Answer

4 seats and possibilities are S(student) or E(empty)

- - - -
SESE
ESES
SEES

So 3 ways and of course the 2 diff students are interchangeable. therefore 3 x2 = 6 ways

FN · Answer

this is the best approach...annorgrams...

duttsit · Answer

OA is 6. Good job guys!!

krisrini · Answer

Its faster to answer this manually. Let S1 and S2 be the two students.

Arranging S1 first and then S2 we get 
D1 D2 D3 D4 (Desks)
S1 B S2 B (B is blank)
S1 B B S2 
B S1 B S2

Similarly we will have 3 more combinations arraging S2 first and followed by S1. So in total there are 6.

How many different ways can 2 students be seated in a row of

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