Word problems: a phone battery drains

Write an equation for the situation, then solve it.

1. A phone is charged to 53%. It loses 2% each hour. After how many hours is it at 31%?
2. A phone is charged to 38%. It loses 2% each hour. After how many hours is it at 30%?
3. A phone is charged to 44%. It loses 4% each hour. After how many hours is it at 24%?
4. A phone is charged to 39%. It loses 2% each hour. After how many hours is it at 21%?
5. A phone is charged to 99%. It loses 6% each hour. After how many hours is it at 27%?
6. A phone is charged to 41%. It loses 3% each hour. After how many hours is it at 20%?
7. A phone is charged to 61%. It loses 7% each hour. After how many hours is it at 26%?
8. A phone is charged to 112%. It loses 7% each hour. After how many hours is it at 21%?
9. A phone is charged to 154%. It loses 11% each hour. After how many hours is it at 33%?
10. A phone is charged to 147%. It loses 11% each hour. After how many hours is it at 37%?
11. A phone is charged to 59%. It loses 4% each hour. After how many hours is it at 35%?
12. A phone is charged to 90%. It loses 5% each hour. After how many hours is it at 40%?
13. A phone is charged to 214%. It loses 11% each hour. After how many hours is it at 27%?
14. A phone is charged to 210%. It loses 7% each hour. After how many hours is it at 35%?
15. A phone is charged to 99%. It loses 9% each hour. After how many hours is it at 27%?
16. A phone is charged to 73%. It loses 3% each hour. After how many hours is it at 34%?
17. A phone is charged to 115%. It loses 11% each hour. After how many hours is it at 27%?
18. A phone is charged to 190%. It loses 18% each hour. After how many hours is it at 28%?
19. A phone is charged to 200%. It loses 12% each hour. After how many hours is it at 20%?
20. A phone is charged to 217%. It loses 7% each hour. After how many hours is it at 35%?