Answer :

Let's analyze the given question step-by-step.

1. Understanding Ratio and Fraction Conversion:
- A ratio is a way to compare two quantities by showing the relative size of one quantity to the other. In this case, the ratio given is "3 out of 31."
- To convert a ratio into a fraction, we take the part (the smaller number) as the numerator and the whole (the larger number) as the denominator.

2. Given Ratio:
- The ratio provided is 3 out of 31.

3. Forming the Fraction:
- According to the ratio "3 out of 31," we can form the fraction by placing 3 (the part) as the numerator and 31 (the whole) as the denominator.
- Therefore, the fraction is:
[tex]\[ \frac{3}{31} \][/tex]

4. Verifying the Statement:
- The question asks us to determine whether the statement "The ratio 3 out of 31 written as a fraction is [tex]\(\frac{3}{31}\)[/tex]" is true or false.
- Based on the conversion from the ratio to the fraction, we see that [tex]\(\frac{3}{31}\)[/tex] correctly represents the ratio of 3 out of 31.

5. Answer:
- This statement is indeed true.

Therefore, the answer to "The ratio 3 out of 31 written as a fraction is [tex]\(\frac{3}{31}\)[/tex]" is:

[tex]\[ \boxed{\text{True}} \][/tex]