Answer:
They would have 84 books all together.
Explanation:
For Jane to have twice as many books as Kate and to give 14 to have an equal amount, she would need to have 28 more books than Kate, meaning she has 56 and Kate has 28. This is because when you take -14 away from 56, you get 42 and when you add 14 to 28 you get 42.