x = number of days it would take Kate to paint the house by herself. .
x+5 = number of days it would take Jean to paint the house by herself.
Together, they paint the house in 6 days:Β
1/x + 1/(x+5) = 1/6Β
Multiply both sides by 6x(x+5)Β
6(x+5) + 6x = x(x+5)Β
12x + 30 = x^2 + 5xΒ
x^2 β 7x β 30 = 0Β
therefore the answer is A.