A Marketing Research firm has these requirements for the validity of a Market Survey.

1) Survey at least 5,000 U.S Households.

2) Survey at least 1,000 households whose heads are less than 30 years old.

3) Survey at least 750 households whose heads are between 31 and 50.

4) Ensure that no more than 20% of those surveyed are 51 years of age.

Cost Per Person Surveyed ($)
Age < = 30	Age 31	Age > = 51
8	9	7.5

Find the minimum interview cost considering business rules.