First, count how much is 55% from 32 ounces:
32 ounces - 100%
x ounces - 55%.
Mathematically you can write proportion:
\(\dfrac{32}{x}=\dfrac{100}{55} ,\\ \\ x=\dfrac{32\cdot 55}{100} =17.6.\)
Then you know that 17.6 ounces was drunk and you can calculate how much water left:
32-17.6=14.4
Answer: left 14.4 ounces of water.
