Final answer:
Adam sold magazines and books last week, but without the price of the books, we cannot calculate the total amount of money he earned.
Step-by-step explanation:
Adam sold 42 magazines and 14 books last week. To calculate the total amount of money Adam earned, we need to find the cost per magazine and book. If the price of a magazine is $4 each, then Adam earned 42 * $4 = $168 from selling magazines. Since we don't know the price of the books, we cannot calculate the total amount of money Adam earned. Therefore, none of the given options (a) £600, b) £700, c) £800, d) £900) can be considered as the correct answer.