Answer:
$11,920
Explanation:
2015 prices:
8 textbooks x $90 = $720
28 credit hours x $400 = $11,200
total = $11,920
the base year, in this case 2015, will be used to adjust the relative prices of the goods and services purchased by students. E.g. for year 2016, the index based on 2015 should be (8 x $90) + (28 x $400) = $11,920 since the quantities didn't change, only the nominal prices.