The demand for textbooks is price inelastic. Which of the following would explain this?

Question

The demand for textbooks is price inelastic. Which of the following would explain this?

a.) Many alternative textbooks can be used as substitutes.

b.) Students have a lot of time to adjust to price changes.

c.) Textbook purchases consume a large portion of most students' income.

d.) The good is a necessity.

Answer 1

It's not all of the above, it is "d", only, because a textbook is a very particular good, very specific.  It is not fungible.  If your teacher/professor tells you to buy book x from author y, what are you going to do?  You're not going to buy book z from author w!  That just won't work.  You could xerox it, but that's against the law.  (This discards alternative "a".

Once asked, students cannot wait until the end of the term.  There are tests to be done and all that.  This means students do not have a lot of time to adjust to price changes (alternative "b" discarded).

As to alternative "c", it is not the percentage of income spent on something that determines its price.  It is demand.  Percentage of income has nothing to do with the demand being elastic or inelastic: specially when the good is a need.  

Because it's such a specific merchandise, it becomes a necessity whenever a teacher/professor tells students to buy them.  Alternative "d" is henceforth correct.

Answer 2

e.) all of the above

Answer 3

d because you have to by them no matter what the price

Answer 4

d) Textbooks are necessary goods, therefore people will buy them even if the prices get higher, because they need them to study.  

If they were talking about pencils, for example, then the demand would be more elastic because you can use substitutes (pens, markers, etc.)