After eating a hearty meal they went to see the Buckingham palace. There, Rachel learned that 49 visitors came to the Buckingham palace that day. If there were 3 visitors the previous day and 12 visitors the day before that How many visited the Buckingham palace before that day?
The day before the day before the day in question, there were 3 visitors. 
The day before the day in question, there were 12 visitors. 
The day in question, there were 49 visitors. 

We can see that the number of visitors is increasing by 9 each day. So, we can set up the equation: 

3 + (3+9) + (12+9) = 49

3 + 12 + 21 = 49

36 = 49

This equation does not make sense, so the answer must be that there is not enough information given to solve the problem.