Question 136978
SORRY SORRY SORRY. i MISREAD THE PROBLEM AND USED SARA'S TIME AS 3 TIMES kATIE INSTEAD OF 3 HOURS LONGER.

the formula for working together is:
x*y/(x+y) time working together.
Sara=k+3
Katie=k
K(K+3)/(K+3+K)=2
(K^2+3K)/(2K+3)=2
K^2+3K=2(2K+3)
K^2+3K=4K+6
K^2+3K-4K-6=0
K^2-K-6=0
(K-3)(K+2)
K-3=0
K=3 HOURS FOR KATIE WORKING ALONE.
3+3=6 HOURS FOR SARA WORKING ALONE.