SOLUTION: Can you help me solve this? Following a severe​ snowstorm, Ken and Bettina Reeves must clear their driveway and sidewalk. Ken can clear the snow by himself in 4 ​hours,
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Question 1009215: Can you help me solve this? Following a severe snowstorm, Ken and Bettina Reeves must clear their driveway and sidewalk. Ken can clear the snow by himself in 4 hours, and Bettina can clear the snow by herself in 6 hours. After Bettina has been working for 2 hours, Ken is able to join her. How much longer will it take them working together to remove the rest of the snow?
I know that their rates are 1/4 and 1/6, but I don't know how to factor Bettina working for 2 hours already. Answer by fractalier(6550) (Show Source):
You can put this solution on YOUR website! We can determine how much of the job they have finished by
2/4 + 2/6 = 1/2 + 1/3 = 5/6 of the job
Thus they have 1/6 of the job to go.
Then we write
t/4 + t/6 = 1/6
Multiply all by 12 (the LCD) and get
3t + 2t = 2
5t = 2
t = 2/5 hour = 24 minutes
