Water and wastewater · Worked step by step
What is the flow if 12,000 gallons fill in 40 minutes?
If math has never been your thing, you are in the right place. Try it on paper first, then we write it out with you, one small step at a time, and explain every step in plain words so you never lose the thread.
The problem
A tank fills with 12,000 gallons in 40 minutes. What is the flow rate in gallons per minute?
Grab a pen and paper first
Give it a real try on paper before you watch. If you get stuck, take a hint. If you go blank, that is fine, press play and we will walk it through together.
Watch it solved, with you
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Press play and I’ll write it out with you, one small step at a time.
Every step gets a plain-words explanation here, so you always know exactly what just happened and why.
The written version, step by step
- 1
Write what you know
amount = 12,000 gal • time = 40 minutes
- 12,000 gallons went in.
- It took 40 minutes.
- We want per minute, so keep minutes.
- 2
Divide gallons by minutes
flow = 12,000 ÷ 40 • flow = 300 GPM
- Per minute means divide by the minutes.
- 12,000 ÷ 40 = 300.
- So the flow is 300 gallons per minute.
Quick trick: Cancel a zero from each: 1,200 ÷ 4 = 300.
Remember this for good
Flow rate = amount divided by time. Gallons divided by minutes gives GPM.
Per means divide. Gallons per minute is gallons divided by minutes.
Solve it fast next time
- Flow = amount divided by time.
- Gallons divided by minutes gives GPM.
- Cancel a zero from each to divide faster.
The answer: 300 GPM.