Water is flowing into and being removed from a tank - Leaving Cert Mathematics - Question 10(a) - 2021
Question 10(a)
Water is flowing into and being removed from a tank.
The volume of water in the tank is measured on a daily basis, starting at day 0.
The volume of water, in litres,... show full transcript
Worked Solution & Example Answer:Water is flowing into and being removed from a tank - Leaving Cert Mathematics - Question 10(a) - 2021
Step 1
Find the value of $t$ when the tank empties.
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Answer
To find when the tank empties, we need to set the volume function to zero:
This simplifies to:
Factoring out t, we get:
Thus, t=0 or t=3101≈33.67 days.
Since t≥0, the tank empties when t≈33.67 days.
Step 2
Find the rate at which the volume of water in the tank is changing when $t = 5$.
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Answer
To find the rate of change, we need to first calculate the derivative of the volume function:
Now, substituting t=5 into the derivative:
Thus, at t=5, the volume of water in the tank is changing at a rate of 71 litres per day.
Step 3
Find the value of $t$ when the volume of water in the tank is a maximum.
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Answer
To find the maximum volume, we set the derivative to zero:
Rearranging gives:
Therefore, the volume of water is maximized at approximately t=16.83 days.
Step 4
Find the maximum volume of the water in the tank, correct to the nearest litre.
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Answer
To find the maximum volume, substitute t≈16.83 back into the original volume function:
Calculating this gives:
≈1000.80+690.03−848.97≈841.86.
Hence, the maximum volume of the water in the tank is approximately 842 litres.
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