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put this solution on YOUR website!A sink is filling at the rate of 1 liter in 5 seconds. It is draining at the rate of 1 liter in 11 seconds. How long for the time it is empty will it take the sink to fill, if its capacity is 8 liters?
:
Let's look the two devices individually
The faucet alone fills the sink: 8 * 5 = 40 sec
The drain alone empties a full sink: 8 * 11 = 88 sec
:
Let t = time to fill the sink when both devices are on
Let the full sink = 1
Filling is +
Draining is -
:
-
= 1
:
Multiply equation by 880
880*
- 880*
= 880(1)
:
CAncel out the denominators and you have:
22t - 10t = 880
:
12t = 880
:
t = 880/12
:
t = 73.33 seconds
:
:
Check using t = 73.33 :
-
= 1
1.83 - .83 = 1
:
How about this? Was it understandable?
