Hint
As we don't know how of the people were library members, you can try a random number and see what happens.
Answer
4,200 books.
Reasoning
It doesn't matter how many library members there were, as 1/2 of them accepted the books, and each accepted 6 books, which is 3 books per member on average.
Similarly, it doesn't matter how many non-members there were as 3/4 of them accepted the books, and each accepted 4 books, which is again 3 books per non-member on average.
Double-Checking
Both the members and non-members accepted, on average, 3 books each.
And 1400 x 3 = 4200.
??
Puzzle 4
At the local mid-summers fayre, four ladies are planning to delight the visitors with their speciality cakes.
Mrs Archer will make a chocolate cake.
Neither Mrs Bowness, Louise nor Kay Cook propose to make a vanilla cake.
Julie, who is not Mrs Dancer, will make coffee.
Mary will not make a plain one.
You need to find their full names and who plans to make which cake.
Answer
Louise Archer will make the chocolate cake.
Julie Bowness will make the coffee cake.
Kay Cook will make the plain cake.
Mary Dancer will make the vanilla cake.
