To multiply \( \frac{3}{5} \) by \( 4 \), you can express \( 4 \) as a fraction, which is \( \frac{4}{1} \).
Now multiply the two fractions:
\[ \frac{3}{5} \times \frac{4}{1} = \frac{3 \times 4}{5 \times 1} = \frac{12}{5} \]
Next, convert \( \frac{12}{5} \) to a mixed number. To do this, divide \( 12 \) by \( 5 \):
\[ 12 \div 5 = 2 \quad \text{(the whole number part)} \] \[ 12 - (5 \times 2) = 12 - 10 = 2 \quad \text{(the remainder)} \]
So, \( \frac{12}{5} \) can be expressed as:
\[ 2 \frac{2}{5} \]
Thus, the answer is:
\[ \boxed{2 \frac{2}{5}} \]