The correct answer is: $3.375$
Explanation
Convert the fractional part to a decimal, then add it to the whole number.
Steps:
- Convert the fraction: $$\frac{3}{8}=3\div8=0.375$$
- Add the whole number: $$3+\frac{3}{8}=3+0.375=3.375$$
Therefore, $3\frac{3}{8}$ as a decimal is $3.375$.