SOLUTION: if man 1 fills a tank in 60min's and man 2 fills in 30min's and man 3 fills in 20mins how long if they fill together please break down as simple as possible for me to understand

Question 955543: if man 1 fills a tank in 60min's and man 2 fills in 30min's and man 3 fills in 20mins how long if they fill together please break down as simple as possible for me to understand
Found 2 solutions by macston, ptaylor:
Answer by macston(5194) (Show Source): You can put this solution on YOUR website!
Man1 fills 1 tank/60 minutes=1/60 tank per minute. We will convert the other fractions to this denominator to add.
Man2 fills 1 tank/30 minutes=1/30 tank per minute.1/30 tank/minute(2/2)=2/60 tank/minute.
Man3 fills 1 tank/20 minutes=1/20 tank per minute.1/20 tank/minute(3/3)=3/60 tank/minute.
Together:
Man1+Man2+Man3=1/60 tank/minute+2/60 tank/minute+3/60 tank /minute=6/60 tank/minute=1/10 tank/minute.
To fill 1 tank at 1/10 tank/minute=(1tank)/(1/10tank/min)=10 minutes
The three together can fill the tank in ten minutes.
Answer by ptaylor(2198) (Show Source): You can put this solution on YOUR website!
Let x= amount of time needed to fill tank if they work together
Together the three men fill at the rate of 1/x of the tank per min
man1 fills at the rate of 1/60 of a tank per min
man2 fills at the rate of 1/30 of a tank per min
man3 fills at the rate of 1/20 of a tank per min
sooooo
1/60 + 1/30 + 1/20= 1/x. multiply each term by 60x
x+2x+3x=60
6x=60
x=10 min---time needed if they work together
CK
In 10 min, man1 fills 10/60=1/6 of the tank
In 10min, man2 fills 10/30=1/3 of the tank
In 10 min, man3 fills 10/20=1/2 of the tank
Now 1/6 +1/3+1/2 should add up to one tank and they do:)
Hope this helps---ptaylor

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