An algebra problem students struggle with

Hi.  I am amused when a student midway through the class will ask what grade he or she needs on the remaining material, so that the final grade will be say a B.  My amusement is because either it is a student in my algebra class asking this question, or a student in my statistics class where algebra is the prerequisite. 

I should use this example as additional ammunition to the question, "Why do we have to take algebra?  I'll never use it."