Some mountains are hillocks. Some mountains are rivers. Some mountains are valleys. Conclusions: 1. All mountains are either hillocks or rivers or valleys 2. No valley is river 3. Some river are valleys

Correct Answer: Only 2 and 3 follow

2 and 3 are the satements involving the extreme terms of the last 2 premises and form a complementary pair. Thus either 2 or 3 follows