Answer:
Josie will have bought 12 souvenirs.
Explanation:
3 days = 9 souvenirs
That means, for each (1) day, Josie will have bought 3 souvenirs.
Essentially you're just multiplying by 3.
3 x 1 = 3
So, 3 x 4 = 12.
Table
Day | 1 2 3 4
Souvenir | 3 6 9 12