word problem

Question

hernando walks his dog every two days. he gives his dog a bath once a week. today , hernando walked his dog and then gave her a bath. how many days will pass before he does both chores on the same day?

Answer 1

Use the LCM of 2 and 7. You can also try to list out the days. Let's say that today is Day 1.

Walks on Days 1, 3, 5, 7, 9, 11, 13, 15

Baths on Days 1, 8, 15

 

The first number to appears on both lists (after Day 1, today) is 15. Since 15 is 14 days after Day 1, 14 days will pass before he does both chores on the same day.

 

Also, the LCM of 2 and 7 is 14.

Multiples of 2: 2, 4, 6, 8, 10, 12, 14, 16, 18, ...

Multiples of 7: 7, 14, 21, 28, ...