Answer:
8 weeks
Step-by-step explanation:
Let x represent how many weeks they will be in France.
The tour in Britain can be represented by 2x, since it is twice as long as the one in France.
The tour in Germany can be represented by x - 2, since it is 2 weeks shorter.
Create an equation and solve for x:
(x) + (2x) + (x - 2) = 30
4x - 2 = 30
4x = 32
x = 8
So, they will be in France for 8 weeks