What is wrong with the answer for this algebraic question In a single line of people waiting to purchase tickets for a movie, there are currently 10 people behind Shandra. If 3 of the people who are currently in line ahead of Shandra purchase tickets and leave the line, and no one else leaves the line, there will be 8 people ahead of Shandra in line. How many people are in the line currently?
I answered it as 19 but the book says 22 . Don't know why because the question asks for the number of people currently in the line, since the 3 people have already left it should be 19 rite? 
 A: "If 3 of the people ... leave the line."  
A: You've written "IF 3 of the people" but actually no one has left the line
A: Its 22. As the question only says "if" 3 people left then..... So the total number of people in the queue is currently  is 10+1(shandra)+8+3(the ones left)=22. 
A: This is a horrible question. I would call it a trick question.
It says that "If three of the people who are currently in line ahead of Shandra purchase tickets and leave the line... there will be 8 people ahead of Shandra in line."
That tells us that there are currently $8+3=11$ people ahead of Shandra in line. We are told that "..there are currently 10 people behind Shandra". That means that currently there are $11$ people ahead of Sandra, there is Sandra herself, and there are $10$ people behind Sandra. Altogether there are, currently, $11+1+10=22$ people in the line.
Why is this a trick question? We often see statements like "If $2x=4$ then $x=2$". As a result, we naturally assume that $2x=4$. In the case of your question, we see "If three of the people who are currently in line ahead of Shandra purchase tickets and leave the line..." and naturally assume that they have left the line.
