The answer should be b. 12
Part 1: I'm pretty sure B is soluble in water.
Part 2: The data is showing that A isn't soluble at all (probably cause it's solid or a lipid or something) because the amount undissolved stays the same as B changes in solubility.
Answer:
1260
Step-by-step explanation:
After you do what the pic says you take 540 and subtract it from 1800 to see the amount left to pay.