A 50-year-old man from Delhi undergoes screening for coronary artery disease (CAD) with an exercise stress test. The test has 85% sensitivity and 70% specificity. In the general population (CAD prevalence ≈ 10%), a positive test result is obtained. Which likelihood ratio BEST explains why a positive stress test in this low-prevalence population is less conclusive than in a high-risk subset (prevalence ≈ 50%)?