When the number of textbooks sold falls/drops 10 percent whenever college tuitions double, textbooks and college enrollments are _____ goods and their cross-elasticity coefficient is mainly _____. (i) Superior; 5.0. (ii) Inferior; 10.0. (iii) Substitute; 5.0. (iv) Complementary; 0.1. (v) Implicit; 7.5.
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