Total there are 5 groups and each group will have atleast one boy and atleast one girl.
Now as there are 6 girls and 5 groups, two girls will be together in one of the groups and remaining four groups will have one girl each.
Now the two girls which will be together can be selected in 6C2 ways..
Now that one boy who will be in the same group as that of the two girls can be selected in 9C1 ways. Now remaining 8 boys will be divided in four groups with two boys each and that can be done in
8C2*6C2 *4C2 *2C2 ways..
So answer will be
6C2 * 9C1 *8C2*6C2 *4C2 *2C2
Now if we simplify this we will get
15*9*8!/16