Answer:
6 days
Step-by-step explanation:
This question becomes much easier when written out per day (shown below). The question tells us that she is reducing her run by half every day, so all we need to is divide the previous day by 2 to get the current day. She starts out with 26 miles so this is our day 1 value.
Day 1 = 26 miles
Day 2 = 13 miles (26÷2=13)
Day 3 = 6.5 miles (13÷2=6.5)
Day 4 = 3.25 miles (6.5÷2=3.25)
Day 5 = 1.625 miles (3.25÷2=1.625)
Day 6 = 0.8125 miles (1.625÷2=0.8125)
We can see that by day 6, her total running amount is less that 1 mile, so the final answer is 6 days.