SOLUTION: A farmer can fplow the filed in 8 days. After working for 3 days,the son joins him amd together the plow the field in 3 more days. How many days will it require for the son to plow

Question 765058: A farmer can fplow the filed in 8 days. After working for 3 days,the son joins him amd together the plow the field in 3 more days. How many days will it require for the son to plow the field alone?
Answer by josgarithmetic(39613) (Show Source): You can put this solution on YOUR website!
THREE MAIN PARTS OF THE FIELD-PLOWING.

FATHER FOR 3 DAYS

Rate is job per day. We can find how much job was done and what still needs to be done.
job was done.
job still needs to be done.
That is job still needs to be done.

FATHER & SON FINISH

They plow the field in 3 days, suggesting they finished the field. We do not know their combined rate nor the son's but we can use a variable for the son's rate.
using r for the son's rate of work, allows us to find the son's rate if he were to work alone.
Solve for r.

which means, the son could plow the field alone in 12 days.

SON ALONE TO FINISH
Right! Already answered. The rate for the son is 1/12 job per day or as the reciprocal, 12 days to plow the field himself.
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