Final answer:
Katy would take 9 days to finish the entire bag of Halloween candy.
Step-by-step explanation:
To find out how many days it would take for Katy to finish the entire bag of candy, we need to multiply the number of days it took her to finish 1/3 of the bag by 3. Since Katy finished 1/3 of the bag in 3 days, we can use the formula:
Total days = Days taken to finish 1/3 of the bag x 3
Substituting the given values:
Total days = 3 x 3 = 9
So, it would take Katy 9 days to finish the entire bag of candy.