[xoannnnna]

The problem says:
Given that the solubility of pure sulfanilamide in 95% ethanol at 78degrees C is 210 mg/ml, calculate the volume of ethanol to dissolve .3g of sufanilamide.

This is what I did:

If 210mg is in 1 ml, then 300 will be dissolved in 1.429 ml. Is that correct? I just crossed multiplied and divided.

[Borek]

Looks OK, although you probably should pay attention to sig figs.