SOLUTION: Kristy can mow a lawn in 1 hour less time than her brother steven. together they can fiinish in 5 hours. how long would it take kristy if she worked alone

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Kristy can mow a lawn in 1 hour less time than her brother steven. together they can fiinish in 5 hours. how long would it take kristy if she worked alone      Log On


   



Question 98660: Kristy can mow a lawn in 1 hour less time than her brother steven. together they can fiinish in 5 hours. how long would it take kristy if she worked alone
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
together=1/5
steven=1/x
kristy=1/x-1
1/x + 1/(x-1)=1/5
multiply 5x(x-1) times both sides: 5(x-1)+5x=x(x-1)
5x-5+5x=x^2-x
-x^2+11x-5=0
Quadratic formula: x=10.5 x-1=9.5
It would take kristy 9.5 hours
Ed