After eating a hearty meal they went to see the Buckingham palace. There were 40 paintings in the Buckingham palace. There, Rachel learned that 31 visitors came to the Buckingham palace that day. If there were 13 visitors the previous day How many more visitors visited the Buckingham palace on that day than on the previous day?
There were 40 paintings in the Buckingham palace. 
There, Rachel learned that 31 visitors came to the Buckingham palace that day. 
If there were 13 visitors the previous day, how many more visitors visited the Buckingham palace on that day than on the previous day?

There were 31 visitors that day, and 13 visitors the previous day. 

There were 18 more visitors that day than the previous day.