SOLUTION: A farmer can plow a field in 40 minutes. His son can plow the same field in 1 hour. How long would it take them to plow the field if they worked together? Formula: (Together/a

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Question 1036630: A farmer can plow a field in 40 minutes. His son can plow the same field in 1 hour.
How long would it take them to plow the field if they worked together?
Formula: (Together/alone)+(Together/alone)= 1 job done
*What I had so far, don't know if it's correct:
t=together
1 hour=60 minutes
(t/40 min.)+(t/60 min.)= 1 job done
Found 2 solutions by ikleyn, jorel555:
Answer by ikleyn(52775) About Me  (Show Source):
You can put this solution on YOUR website!
.
A farmer can plow a field in 40 minutes. His son can plow the same field in 1 hour.
How long would it take them to plow the field if they worked together?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 

The rate of the farmer is 1%2F40 of the field per minute.

The rate of the son is 1%2F60 of the field per minute.

When working together, their rate is the sum 1%2F40+%2B+1%2F60 = 3%2F120+%2B+2%2F120 = 5%2F120 = 1%2F24.

Hence, it takes 24 minutes for them to plow the field if they work together.

You can find many other similar solved joint-work problems in the lessons
    - Using Fractions to solve word problems on joint work,
    - Solving more complicated word problems on joint work,
    - Selected joint-work word problems from the archive
in this site.

Read them and get trained in solving joint-work problems.


Answer by jorel555(1290) About Me  (Show Source):
You can put this solution on YOUR website!
t/40+t/60=1;
3t+2t=120
5t=120
t=120/5=24 minutes working together!!!!!!!!!