What is the percent by volume of isopropyl alcohol in a solution that contains 45 ml of isopropyl alcohol in 1.4 L of water?

3.11%

Explanation:

We express a solution's volume by volume percent concentration, % v/v,

Take the ratio of the isopropyl alcohol (IPA) volume to the total volume of the solution, which is 1400 mL of water + 45 mL of IPA,

and multiply by 100 to get the percentage: 45 / (1400+45) * 100 = 0.0311*100 = 3.11%