Answer:
40 days
Explanation:
This is a least common multiple problem. To do this, you need to find the number where it's a multiple of both.
Multiples of 8 are: 8, 16, 24, 32, 40...
Multiples of 5 are: 5, 10, 15, 20, 25, 30, 35, 40.
Both have the number 40.