I want to know the answer to the following question:
How many kilograms of uranium may be contained in the oceans?
All the background I'm provided with is that "The Earth's crust from the surface to 25 km (15 mi) down is calculated to contain 1017 kg (2×1017 lb) of uranium while the oceans may contain 1013 kg (2×1013 lb).". Is that enough to answer the question?
Answer: yes