SOLUTION: It takes a person 20 minutes to check a batch of 60 workers. An assistant can check the same batch in 30 minutes. How long should it take them working together? Simplest forma

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Question 947895: It takes a person 20 minutes to check a batch of 60 workers. An assistant can check the same batch in 30 minutes. How long should it take them working together?
Simplest format please.
Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!
It takes a person 20 minutes to check a batch of 60 workers. An assistant can check the same batch in 30 minutes. How long should it take them working together?
Let x=amount of time it takes them working together
Together they check at the rate of 1/x of the batch per min
The person checks at the rate of 1/20 batch per min
Assistant checks at the rate of 1/30 of the batch per min
Soooo
1/20 + 1/30= 1/x multiply each term by 60x
3x+2x=60
5x=60
x=12 min ---amount of time it takes them working together
CK
In 12 min person checks 12/20 of the batch
In 12 min assistant checks 12/30 of the batch
12/20 + 12/30 should equal 1 (1 batch, that is)
36/60+24/60=???1
60/60=1
1=1
Hope this helps----ptaylor