SOLUTION: Jeff and Kirk can build a 75ft wall together in 10 Hours. Because Jeff has more experience, he could build wall by myself 3 hours quicker than Kirk. How long would it take Kirk to

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Jeff and Kirk can build a 75ft wall together in 10 Hours. Because Jeff has more experience, he could build wall by myself 3 hours quicker than Kirk. How long would it take Kirk to      Log On


   

Question 1165441: Jeff and Kirk can build a 75ft wall together in 10
Hours. Because Jeff has more experience, he could build wall by myself 3 hours quicker than Kirk. How long would it take Kirk to build the wall by himself ?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
k, the time needed for Kirk working alone 
PERSON            RATE
Jeff              1/(k-3)
Kirk              1/k
Combined          1/10

The size of the wall 75 feet only represents the ONE JOB. How MUCH of the job is not emphasized in the description.

Solve for k, in 1%2F%28k-3%29%2B1%2Fk=1%2F10.
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k%5E2-23k%2B30=0
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General solution for quadratic equation formula gives 21.6 hours for Kirk to do the one job by himself.