jmc

Dividing by $\frac{3}{5}$ is the same as multiplying by its reciprocal, $\frac{5}{3}$. Multiplying a number by two numbers is the same as multiplying the number by the product of those two numbers. Thus, multiplying by $\frac{3}{4}$ and then $\frac{5}{3}$ is the same as multiplying by $\frac{3\cdot 5}{4\cdot 3}=\frac{5}{4}$, and the answer is $\boxed{\text{multiplying by }\frac{5}{4}}$.