To find the fraction of the blanket that is yellow, we first need to determine the total fraction of the blanket that is already covered by green and blue.
- The fraction of the blanket that is green is \( \frac{3}{8} \).
- The fraction of the blanket that is blue is \( \frac{1}{4} \).
To add these fractions, we need a common denominator. The denominator for \( \frac{1}{4} \) can be converted to eighths by multiplying both the numerator and denominator by 2:
\[ \frac{1}{4} = \frac{2}{8} \]
Now we can add the fractions together:
\[ \frac{3}{8} + \frac{2}{8} = \frac{5}{8} \]
Next, we subtract this total from the whole blanket (1, which is the same as \( \frac{8}{8} \)) to find the yellow part:
\[ 1 - \left(\frac{3}{8} + \frac{2}{8}\right) = \frac{8}{8} - \frac{5}{8} = \frac{3}{8} \]
This means the yellow part of the blanket is \( \frac{3}{8} \).
Therefore, the fraction representing the yellow part of the blanket is:
\( \frac{3}{8} \) (3 eighths).