Question

A solution of cough syrup has 23% alcohol. Another solution has 9% alcohol. How many litres of the second solution must be added to 36 litres of the first solution to make a solution of 14% alcohol?

Answer 1

The new 45 litre solution is 42% alcohol.

We figure this out by determining how much alcohol is in both solutions.

36% of 15l = 5.4l and 45% of 30l is 13.5l

5.4l + 13.5l =18.9l

So 18.9l of our final 45 litre solution is alcohol. Now we just do 18.9/45 to get our final percentage. 18.9/45=42%