SOLUTION: A farmer plows the field using a tractor in 5 days. His father can do the same job in 9 days. How many days will it take them working together?

Question 896101: A farmer plows the field using a tractor in 5 days. His father can do the same job in 9 days. How many days will it take them working together?
Answer by Edwin McCravy(20060) (Show Source): You can put this solution on YOUR website!
A farmer plows the field using a tractor in 5 days.

The farmer's rate is 1 field per 5 days or 

 =

His father can do the same job in 9 days.

His father's rate is 1 field per 9 days or 

 =

How many days will it take them working together?

Let the answer be x days.

Then their combined rate is 1 field per x days or 

 = 

The equation comes from:

  

So

     

        

Multiply through by LCD = 45x


        
             
            

             

             

Edwin

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