In a hall there are 100 chairs marked as 1,2,3...upto 100.The chairs are arranged as 10 in row and 10 in columns.There are 100 students of rannks 1 to 100 (means their ranks in the class).Now the 100 boys enters the hall one by one according to their ranks.Now the 1st boy enters the hall and he can sit in any one of the 100 chairs according to his will.But the 2nd boy has to sit in the chair marked as 3.Again yhe 3rd boy can sit in any of the remaining 98 chairs,but the 4th one has to sit in chair 4.The same process continues for the other students.If no two student having consecutive rank can sit adjacently,then the number of such arrangements possible is?

Aniket Patra , 14 Years ago

Grade Upto college level