Answer:
Explanation:
the first time you add 10, the second time you add 20, the third time you add 40, and you keep doubling up to the eighth time
- 15 + 10 = 25
- 25 + 20 = 45
- 45 + 40 = 85
- 85 + 80 = 165
- 165 + 160 = 325
- 325 + 320 = 645
- 645 + 640 = 1285
- 1285