Compared to pure water, a salt water solution will have a
a. higher freezing point and a lower vapor pressure and boiling point.
b. lower vapor pressure and freezing point and a higher boiling point.
c. higher vapor pressure, freezing point and boiling point.
d. lower vapor pressure, freezing point and boiling point.

lower vapor pressure and freezing point and a higher boiling point

Explanation:

All the properties listed above are colligative properties, they depend on the amount of solute present in a solution.

It is known that a solution has a lower vapour pressure than the corresponding pure solvent due to the presence of a solute. Also the freezing point of a solution is decreased while its boiling point is increased when compared with those of the pure solvent.

the answer would be c

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form