One pipe can fill a pool in 20 minutes, a second can fill the pool in 30 minutes, and a third can fill it in 10 minutes. How long would it take the three together to fill the pool?
1/(1/20+1/30+1/10)
=60/11 minutes
How many pounds of birdseed are used to fill each feeder? draw a tape diagram to show your thinking
To find out how long it would take the three pipes together to fill the pool, we need to calculate their combined filling rate.
First, let's find the rate of each pipe by determining how much of the pool they can fill in one minute.
The first pipe can fill the pool in 20 minutes, so its rate is 1/20 of the pool per minute.
The second pipe can fill the pool in 30 minutes, so its rate is 1/30 of the pool per minute.
The third pipe can fill the pool in 10 minutes, so its rate is 1/10 of the pool per minute.
To find their combined rate, we add up the rates of all three pipes:
1/20 + 1/30 + 1/10 = 3/60 + 2/60 + 6/60 = 11/60
Now, we know that the combined rate of the three pipes is 11/60 of the pool per minute. To find out how long it would take them to fill the entire pool, we simply invert this rate:
60/11
Therefore, it would take the three pipes approximately 5.45 minutes (or 5 minutes and 27 seconds) to fill the pool when working together.