After how many hours is the battery power at 75% if the battery decreases by 20% per hour

2.5

Step-by-step explanation:

If the battery starts completely charged then after one hour it will be at 80% so at two hours it will be at 60. and there is 60 minutes in one hour so it goes down 10% in 30 minutes so it goes down 5% in 15 so it goes down 2.5% in 7.5

1. 8

2. 9

3. 20

4. 3

5. 17

6. 2.2

7. 11.25

8. 1

9. 14

10. 2

step-by-step explanation:

thats the first half