1. **State the problem:** Find the sum of the first 10 terms of the sequence 3/2, 3/2, 3/2, ... 2. **Identify the type of sequence:** This is a constant sequence where every term is the same, $\frac{3}{2}$. 3. **Formula for the sum of the first $n$ terms of a constant sequence:** $$ S_n = n \times a_1 $$ where $a_1$ is the first term and $n$ is the number of terms. 4. **Apply the formula:** $$ S_{10} = 10 \times \frac{3}{2} $$ 5. **Calculate:** $$ S_{10} = \cancel{10} \times \frac{3}{2} = \frac{10 \times 3}{2} = \frac{30}{2} = 15 $$ 6. **Interpretation:** The sum of the first 10 terms is 15. 7. **Answer choice:** B. 15