A meeting with 10 teachers will take place in a conference hall. How many different ways these teachers could be seated around a round table if 4 of them always was seated together?
1920
2160
2880
3240
We can arrange the 4 boys in =24 ways. Then, we can insert the 4 girls into the 5 spaces between the boys, in any order, in ways. However, for each of these arrangements, the two end spaces cannot be occupied by girls. Therefore, we must subtract the arrangements where a girl is in one of the two end spaces. There are 2 ways to select which end space is occupied, and ways to arrange the boys and girls in the remaining spaces. Therefore, the total number of ways is
Study 40% syllabus and score up to 100% marks in JEE