afrazer721
New member
- Joined
- Feb 1, 2012
- Messages
- 26
A drainpipe can empty a full tank of liquid waste in 15 minutes. The chemical factory that produces the waste has two feeder pipes-one can fill the tank by itself in 18 minutes and the other by itself in 24 minutes. With all three pipes open, how long before the tank will be filled?
"To solve this particular type of [work-related word] problem think about how much of the job will be completed in 1 [minute]. For example, if someone or something can complete a job in 5 [minutes], then 1/5 of the job is completed in one [minute]. If a person or thing can complete a job in x minutes, then 1/x of the job is completed in one minute."
Let's try and solve the work-problem. In one minute one feeder pipe completes 1/18 of the tank filling. In one minute the second feeder pipe completes 1/24 of tank filling. If I let x equal the time it takes both feeder pipes to fill the tank then 1/x is the amout the tank is filled in one minute.
I got a little confused at this point because I'm wondering if I should only set up an equation such as 1/18+1/24=1/x or
1/15-(1/18+1/24)=1/x. I'm going to use the former. So, multiply each term by the LCD, 72x. Combine like terms 4x+3x=72,
7x=72.
x=10.2 minutes or approximately 10 minutes and 30 seconds for feeder pipes to fill tank and 15 minutes for drainpipe to empty full tank with liquid waste.
"To solve this particular type of [work-related word] problem think about how much of the job will be completed in 1 [minute]. For example, if someone or something can complete a job in 5 [minutes], then 1/5 of the job is completed in one [minute]. If a person or thing can complete a job in x minutes, then 1/x of the job is completed in one minute."
Let's try and solve the work-problem. In one minute one feeder pipe completes 1/18 of the tank filling. In one minute the second feeder pipe completes 1/24 of tank filling. If I let x equal the time it takes both feeder pipes to fill the tank then 1/x is the amout the tank is filled in one minute.
I got a little confused at this point because I'm wondering if I should only set up an equation such as 1/18+1/24=1/x or
1/15-(1/18+1/24)=1/x. I'm going to use the former. So, multiply each term by the LCD, 72x. Combine like terms 4x+3x=72,
7x=72.
x=10.2 minutes or approximately 10 minutes and 30 seconds for feeder pipes to fill tank and 15 minutes for drainpipe to empty full tank with liquid waste.
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