I need help with a math problem.?

Question

Tara has decided to start a walking program. Her initial walking time is 5 minutes. She plans to double her walking time and add 1 minute every 5 days. Provided that Tara achieves her goal, how many minutes will she be walking on days 21 through 25?

I've been stuck on this problem for 20 minutes now =(

Answer 1

Here is the issue, do the minutes change on the 5th day of the walk or the 6th (meaning she keeps the pace for 4 days and then doubles + 1 on day five, or keeps pace for 5 days and then doubles on the following day).  the first column shows changing after 5 days of walking, the second shows changing on the 5th day.

Another issue "Provided that Tara achieves her goal, how many minutes will she be walking on days 21 through 25" is that per day or total?

Day Minutes Minutes

1 5 5

2 5 5

3 5 5

4 5 5

5 5 11

6 11 11

7 11 11

8 11 11

9 11 23

10 11 23

11 23 23

12 23 23

13 23 47

14 23 47

15 23 47

16 47 47

17 47 95

18 47 95

19 47 95

20 47 95

21 95 191

22 95 191

23 95 191

24 95 191

Answer 2

10 minutes

Answer 3

days 1 - 5: 5 minutes

days 6 - 10: 11 minutes (5 x 2 + 1)

days 11 - 15: 23 minutes (11 x 2 + 1)

days 16 - 20: 47 minutes (23 x 2 + 1)

days 21 - 25: 95 minutes (47 x 2 + 1)

Answer 4

maybe 95 minutes? thats my guess

Answer 5

5 days=11 minutes

21x11=231

25x11=275

Answer 6

W(1) = 5 min

W(6) = 2(W(1)) + 1 min = 11 min

W(11) = 2(W(6)) + 1 min = 23 min

W(16) = 2(W(11)) + 1 min = 47 min

W(21) = 2W(16) + 1 min = 95 min