Final answer:
Lena eats an apple every other day. The next Monday she will eat an apple again is on October 9.
Step-by-step explanation:
Lena eats an apple every other day. Today is Monday, October 1 and Lena eats an apple today. To find out when Lena will eat an apple on a Monday again, we need to determine how many days it will take for a Monday to occur. Since Lena eats an apple every other day, we know that there are two days between each apple she eats.
Therefore, we need to find the next multiple of 2 that is greater than 7, which is the number of days in a week. The next multiple of 2 after 7 is 8. So, it will take 8 days for a Monday to occur again. Counting from October 1, the next Monday will be on October 9. Therefore, Lena will eat an apple on a Monday again on October 9.