I am trying to create a excel calculator, that will count time needed to complete a certain case. This is quite basic match but I might be wrong in my attempt.

Lets start with this.

We have a fixed time 15 minutes

Our task has to be completed at 6:40 minutes which will be a variable. Of course the timer is decreasing.

So after the time get to a point 6:40 minutes left it has to be 100% Our interval will be 30 seconds - Lets say its in column A.

```
15:00 0 %
14:30 xx,xx %
13:30 xx,xx %
12:30 xx,xx %
11:30 xx,xx %
10:30 xx,xx %
09:30 xx,xx %
08:30 xx,xx %
07:30 xx,xx %
06:30 99,?? %
05:30 Success
04:30 Success
03:30 Success
02:30 Success
01:30 Success
00:30 Success
00:00 Success
```

Basically I need a formula for column B that will count a %, that all will be based on the variable 6:40 which will be counter a % off..

If the explanation is not clear please tell me.

Online sheet https://docs.google.com/spreadsheets/d/1El-1WVgICJ5vrYs5vALYQ2kMrJZYqAk17Hvz5gXwFZs/edit#gid=0

`t`

you calculate what your success rate is by`=100-((t-400s)/5))`

right?