Answer:
2 ways
Step-by-step explanation:
The best way to do this is to fix the position of the stranger and then arrange the two identical twins
The number of ways of knowing where the stranger will seat is 1! ways = 1 way
The number of ways of arranging the two identical twins is 2! ways = 2*1 = 2 ways
The number of sitting arrangements = 1 * 2 = 2 ways