Answer:
B) 8.3%
Step-by-step explanation:
The multifactor productivity is given the ratio between output (amount charged per each house cleaned) and input (chemical, labor and misc. expenses)
Let x be the amount charged per housed cleaned, the original and new productivities are:
![P_(old)=(x)/(10+40+5)=0.018182x \\P_(new)=(x)/(1.5*10+40+5)=0.016667x](https://img.qammunity.org/2021/formulas/business/college/4tus2fbmnrob3jgbk72gblwt9jd0lc7f3o.png)
The rate by which the multifactor productivity has fallen is:
![R = (P_(new)-P_(old))/(P_(old))\\R=(0.0166667-0.018182)/(0.018182) \\R=-0.083=-8.3\%](https://img.qammunity.org/2021/formulas/business/college/m85xpyot1swriwjvdplnh7vtmpgtsezzqs.png)
The multifactor productivity has fallen by 8.3%.