Kalon and his friend Marna own a chimney sweep service company. Working together, they can clean a 20-foot chimney in 1Five-sevenths hours. If it takes Kalon 4 hours to clean a 20-foot chimney by himself, how long does it take Marna to clean the same size chimney by herself?
Rate
(Chimneys per Hour)
Time
(Hours)
Fraction Completed
Kalon
One-fourth
1 and five-sevenths
Three-sevenths
Marna
x
1 and five-sevenths
StartFraction 12 x Over 7 EndFraction
3 hours
4 hours
5 hours
6 and six-sevenths hours