Final answer:
Susan's juice will last for 6 days.
Step-by-step explanation:
To find out how many days Susan's juice will last, divide the total amount of juice she has (4 liters) by the amount she drinks each day (0.7 liters).
4 / 0.7 = 5.71 (approximately)
Since she can't have a fraction of a day, we round up to the next whole number. Therefore, her juice will last for 6 days.