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?
1/2
2/3
3/2
2/1
The total number of students who took the test is the sum of the students who passed and the students who did not pass, so the total is 32 + 16 = <<32+16=48>>48 students.
The ratio of students who passed to the total number of students who took the test is 32/48.
To simplify this fraction, we can divide both the numerator and the denominator by their greatest common divisor, which is 16.
32/48 = (32/16)/(48/16) = 2/3.
Therefore, the ratio of the number of students who passed the test to the total number of students who took the test is 2/3. Answer: \boxed{2/3}.