Prepare a Decision Table for the Airfare Discount problem. Also write the total number of columns in this decision table.

The passengers are treated according to three categories: Type of Flight, Frequent Flyer and Age Group.

The possible values of each category are:

Type of Flight: International (I), Local (L)

Frequent Flyer: Yes (Y), No (N)

Age Group: I (Infant: < 2 years), Y (Youth: between 2 and 16), O (Others: > 16)

The system has four different types of discounts:

80%: Infant passengers travelling in Local flight are eligible

70%: Infant passengers travelling in International flight are eligible

20%: Young Frequent Flyers, travelling in International flight

15%: Other Frequent Flyers, travelling in any flight