Water and wastewater · Worked step by step
What is the flow if 6,000 gallons fill in 30 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 6,000 gallons of water in 30 minutes. What is the flow rate in gallons per minute (GPM)?
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
Every step is written out slowly and explained in plain words, so you always know what just happened. Nobody skips ahead and leaves you behind.
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 down what you know
amount = 6,000 gal • time = 30 minutes
- We put 6,000 gallons in.
- It took 30 minutes.
- We want gallons per minute, so keep the time in minutes.
Quick trick: The unit they ask for (per minute) tells you which time unit to use.
- 2
Divide gallons by minutes
flow = 6,000 ÷ 30 • flow = 200 GPM
- "Per minute" means divide by the minutes.
- 6,000 ÷ 30 = 200.
- So the flow is 200 gallons per minute.
Quick trick: 6,000 ÷ 30: cross off a zero from each to get 600 ÷ 3 = 200. Much easier.
Remember this for good
Flow rate = amount ÷ time. Gallons divided by minutes gives gallons per minute.
"Per" means divide. Gallons PER minute = gallons ÷ minutes. The word tells you the math.
Solve it fast next time
- Flow = amount ÷ time. Whatever the time unit is, that is the flow's unit.
- Gallons ÷ minutes = GPM. Gallons ÷ days = GPD.
- If it asks per minute but gives hours, change the hours to minutes first.
The answer: 200 GPM.