Answer:
62.98 and 76.8356 (I do not know what accuracy you need)
Explanation:
- It dropped 6% in 1847, so 1847’s depth is 94% of 1846’s depth
- 94% of 6.7 is 62.98
- It rose 22% in 1848, so this year’s depth is 122% of 1847’s depth
- 122% of 62.98 is 76.8356