Answer:
Step-by-step explanation:
Given that Kalon and his friend Marna own a chimney sweep service company. Working together, they can clean a chimney in 1 5/7 hours and it takes Kalon 4 hours to clean a 20-foot chimney by himself.
i.e. Kalon can do in one hour 1/4 of the work
Marna can do in one hour 1/x of the work
(assuming total x hours Marns taes to clean the same size chimney)
Together they clean
[tex]\frac{7}{12}[/tex]
[tex]\frac{1}{4} +\frac{1}{x} =\frac{7}{12}[/tex]
Simplify to get
[tex]12(x+4)=28x\\3x+12=7x\\4x=12\\x=3[/tex]
Marna takes 3 hours to clean the same size chimney
