An industrial synthesis of a pharmaceutical active ingredient involves a three-stage process:
Step 1: P→Q(85% yield) \text{Step 1: } \text{P} \rightarrow \text{Q} \quad (85\% \text{ yield}) Step 1: P→Q(85% yield) Step 2: Q→R(60% yield) \text{Step 2: } \text{Q} \rightarrow \text{R} \quad (60\% \text{ yield}) Step 2: Q→R(60% yield) Step 3: R→S(75% yield) \text{Step 3: } \text{R} \rightarrow \text{S} \quad (75\% \text{ yield}) Step 3: R→S(75% yield)What is the overall percentage yield of the final product S\text{S}S from the starting material P\text{P}P?
20%20\%20%
38%38\%38%
51%51\%51%
73%73\%73%