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?	Options
A) 2  B) 3  C) 4  D) 6  E) 12
Total cases : 12 ( student one has 4 options and student two has three options, 4x3=12)   Non-favourable cases : 6 (when two students sit together. students in desk 1 and desk 2 , in desk 2 and desk 3, in desk 3 and desk 4) for each of these cases there are two possibilities because the positions can be interchanged. hence 2x3=6.   SO favourable cases :  12-6= 
<gadget id="calculator"> 12-6</gadget>
<output>6</output>
6. ANSWER:6
<result>D</result>
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?