Sentence 1: But if the rocks could be conjured, what was the need of all the slaves and the sadistic overseers?

Sentence 2: Why did he need all the slaves if not to bring rocks.
Is this second sentence entailed by the first?

Answer: yes

Sentence 1: (Before the island's telephone service was boldly upgraded, it used to be easier to drive across the border than to put through a call to the other side. )

Sentence 2: ( It used to be difficult to place a call to the other side of the island.)
Is this second sentence entailed by the first?

Answer: yes

Sentence 1: The Edinburgh-based James Thin has the largest bookstore in Scotland (on George Street, opposite the university buildings of Chambers Street).

Sentence 2: There is a larger bookstore in south Wales.
Is this second sentence entailed by the first?

Answer:
it is not possible to tell