Multiply and simplify: \( \frac{15 a}{d} \cdot \frac{2 d}{5 c} \)

To multiply the fractions, you multiply the numerators and the denominators separately: \[ \frac{15 a}{d} \cdot \frac{2 d}{5 c} = \frac{15 a \cdot 2 d}{d \cdot 5 c} \] This gives us: \[ \frac{30 a d}{5 d c} \] Now, we can simplify. The \(d\) in the numerator and the \(d\) in the denominator cancels out: \[ \frac{30 a}{5 c} \] Next, simplify \(30\) and \(5\): \[ \frac{30 a}{5 c} = \frac{6 a}{c} \] So, the final simplified answer is: \[ \frac{6 a}{c} \]