Answer:
B) 8.3%
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:
[tex]P_{old}=\frac{x}{10+40+5}=0.018182x \\P_{new}=\frac{x}{1.5*10+40+5}=0.016667x[/tex]
The rate by which the multifactor productivity has fallen is:
[tex]R = \frac{P_{new}-P_{old}}{P_{old}}\\R=\frac{0.0166667-0.018182}{0.018182} \\R=-0.083=-8.3\%[/tex]
The multifactor productivity has fallen by 8.3%.