There are 20 persons among whom are two brothers. The number of ways in which we can arrange them around a circle so that there is exactly one person between the two brothers, is

There are 20 people among whom two are sisters. Find the number of ways in which we can arrange them around a circle so that there is exactly one person between the two sisters.

There are 20 persons, among whom two are brothers. Find the number of ways in which we can arrange the 20 persons around a round table so that there is exactly one person between the two brothers.

There are fifty persons among whom 2 are brothers. The number of ways they can be arranged in a circle, if there is exactly one person between the two brothers, is

There are fifty persons among whom 2 are brothers. The number of ways they can be arranged in a circle, if there is exactly one person between the two brothers, is

There are 10 persons among whom two are brothers. The total number of ways in which these persons can be seated around a round table so that exactly one person sits between the btothers, is equal to:

There are 20 persons, among whom two are brothers. Find the number of arrangements of these persons in a row.

The number of ways in which 7 persons can sit around a rouund table is