On last week's math test, 32 students received passing grades and 16 students did not receive passing grades. What is the ratio of the number of students who passed the test to the total number of students who took the test?
There were a total of 32 passing + 16 failing = <<32+16=48>>48 students.
The ratio of students who passed the test to the total number of students taking the test is 32/48 = <<32/48=2/3>>2/3. Answer: \boxed{\frac{2}{3}}.