To find the ratio of the number of students going on the field trip to the total number of students, we have:
Number of students going on the field trip = 22
Total number of students = 64
Now, we can express the ratio as:
\[ \text{Ratio} = \frac{22}{64} \]
Next, we simplify this fraction. Both numbers can be divided by their greatest common divisor (GCD), which is 22:
\[ \frac{22 \div 22}{64 \div 22} = \frac{1}{2.909} \approx 1:2.909 \]
However, this ratio should ideally be presented in a simple integer form. Let's simplify it directly by calculating:
22 to 64 simplifies to:
\[ \text{GCD of 22 and 64} = 2 \]
Thus,
22 ÷ 2 = 11
64 ÷ 2 = 32
This simplifies the ratio to:
\[ 11:32 \]
Therefore, the ratio of the number of students who are going on the field trip to the total number of students is:
\[ \boxed{11:32} \]