Final answer:
- Mrs. Johnson should buy 5 boxes of board games to get 20 board games.
- 2 boxes of decks of playing cards to get 20 decks, ensuring she has an equal amount of both.
Step-by-step explanation:
For Part A
To find the least number of board games Mrs. Johnson can buy, we must find the smallest common multiple of 4 and 10 since board games are sold in boxes of 4 and decks of playing cards in boxes of 10. The least common multiple (LCM) of 4 and 10 is 20.
Therefore, Mrs. Johnson can buy 5 boxes of board games to have 20 board games.
For Part B
Since Mrs. Johnson is buying 20 board games, which is 5 boxes of 4 games each (20 / 4 = 5), she will need to purchase 2 boxes of playing cards since each box contains 10 decks of cards (20 / 10 = 2).
The least number of board games Mrs. Johnson can buy is 20, and she should buy 2 boxes of decks of playing cards to match the number of board games.