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guddo
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Beginning at noon yesterday, water was added to a partially filled 19 Dec 2023, 11:11
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Beginning at noon yesterday, water was added to a partially filled water tank at the constant rate of 500 gallons per hour. When there was a total of 2,000 gallons of water in the tank, no more was added. Was there more than 1,000 gallons of water in the tank at noon yesterday?

(1) There were 1,700 gallons of water in the tank at 1:00 yesterday afternoon.
(2) There were 2,000 gallons of water in the tank at 3:00 yesterday afternoon.

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Beginning at noon yesterday, water was added to a partially filled 19 Dec 2023, 11:23
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guddo
Beginning at noon yesterday, water was added to a partially filled water tank at the constant rate of 500 gallons per hour. When there was a total of 2,000 gallons of water in the tank, no more was added. Was there more than 1,000 gallons of water in the tank at noon yesterday?

(1) There were 1,700 gallons of water in the tank at 1:00 yesterday afternoon.
(2) There were 2,000 gallons of water in the tank at 3:00 yesterday afternoon.

Show Spoiler
Attachment:
2023-12-19_17-44-06.png

Beginning at noon yesterday, water was added to a partially filled water tank at the constant rate of 500 gallons per hour. When there was a total of 2,000 gallons of water in the tank, no more was added. Was there more than 1,000 gallons of water in the tank at noon yesterday?

(1) There were 1,700 gallons of water in the tank at 1:00 yesterday afternoon.

Since 500 gallons of water were added in the hour from noon to 1:00 pm, there were 1,700 - 500 = 1,200 gallons of water in the tank at noon, which is more than 1,000 gallons. Sufficient.

(2) There were 2,000 gallons of water in the tank at 3:00 yesterday afternoon.

If the 2,000 gallons mark was reached at 12:30 pm, meaning the water addition lasted only half an hour, then the initial amount in the tank was 2,000 - 1/2*500 = 1,750 gallons, more than 1,000 gallons. However, if the 2,000 gallons mark was reached at 3:00 pm, meaning the water addition lasted three hours, then the initial amount in the tank was 2,000 - 3*500 = 500 gallons, less than 1,000 gallons. Not sufficient.

Answer: A.
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Beginning at noon yesterday, water was added to a partially filled 24 Dec 2023, 00:59
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Similar question to practice (also from GMAT Prep Focus): https://gmatclub.com/forum/beginning-at ... 23200.html
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Beginning at noon yesterday, water was added to a partially filled 28 Mar 2024, 15:27
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Hi Bunuel, why can't we use the explanation in Statement 2 in Statement 1? What if water was added only for half an hour
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Beginning at noon yesterday, water was added to a partially filled 28 Mar 2024, 21:13
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Bunuel
guddo
Beginning at noon yesterday, water was added to a partially filled water tank at the constant rate of 500 gallons per hour. When there was a total of 2,000 gallons of water in the tank, no more was added. Was there more than 1,000 gallons of water in the tank at noon yesterday?

(1) There were 1,700 gallons of water in the tank at 1:00 yesterday afternoon.
(2) There were 2,000 gallons of water in the tank at 3:00 yesterday afternoon.

Show Spoiler
Attachment:
2023-12-19_17-44-06.png
Beginning at noon yesterday, water was added to a partially filled water tank at the constant rate of 500 gallons per hour. When there was a total of 2,000 gallons of water in the tank, no more was added. Was there more than 1,000 gallons of water in the tank at noon yesterday?

(1) There were 1,700 gallons of water in the tank at 1:00 yesterday afternoon.

Since 500 gallons of water were added in the hour from noon to 1:00 pm, there were 1,700 - 500 = 1,200 gallons of water in the tank at noon, which is more than 1,000 gallons. Sufficient.

(2) There were 2,000 gallons of water in the tank at 3:00 yesterday afternoon.

If the 2,000 gallons mark was reached at 12:30 pm, meaning the water addition lasted only half an hour, then the initial amount in the tank was 2,000 - 1/2*500 = 1,750 gallons, more than 1,000 gallons. However, if the 2,000 gallons mark was reached at 3:00 pm, meaning the water addition lasted three hours, then the initial amount in the tank was 2,000 - 3*500 = 500 gallons, less than 1,000 gallons. Not sufficient.

Answer: A.

Hi Bunuel, why can't we use the explanation in Statement 2 in Statement 1? What if water was added only for half an hour
­
In statement (1), we can definitively determine that the pump was active for the full hour between noon and 1:00 PM because the 1,700 gallons present at 1:00 PM are less than the 2,000-gallon capacity of the tank when the pumping ceases. Therefore, at noon, there must have been 1,700 - 500 = 1,200 gallons in the tank.

However, in statement (2), although we know there were 2,000 gallons in the tank at 3:00 PM, we can't ascertain how long the pump operated. It could have filled the tank completely by 12:30 PM and then ceased, or it could have continued for the entire three hours until 3:00 PM. The information provided in statement (2) doesn't give us a clear picture of the pump's operation time. Therefore, it doesn't allow us to determine the amount of water in the tank at noon accurately. It could have been pumping for the entire duration, or it could have reached the 2,000-gallon mark earlier, remaining at that level until 3:00 PM.
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Beginning at noon yesterday, water was added to a partially filled 23 Oct 2024, 14:52
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Bunuel, what if for Statement 2 said "there were 2000 gallons of water in the tank at 2:00 yesterday afternoon"

Given that the question asks for "MORE than 1000 gallons of water" and it could be exactly 1000 gallons at 12:00, then would it be also insufficient?

Thanks in advance!
Bunuel
guddo
Beginning at noon yesterday, water was added to a partially filled water tank at the constant rate of 500 gallons per hour. When there was a total of 2,000 gallons of water in the tank, no more was added. Was there more than 1,000 gallons of water in the tank at noon yesterday?

(1) There were 1,700 gallons of water in the tank at 1:00 yesterday afternoon.
(2) There were 2,000 gallons of water in the tank at 3:00 yesterday afternoon.

Show Spoiler
Attachment:
2023-12-19_17-44-06.png

Beginning at noon yesterday, water was added to a partially filled water tank at the constant rate of 500 gallons per hour. When there was a total of 2,000 gallons of water in the tank, no more was added. Was there more than 1,000 gallons of water in the tank at noon yesterday?

(1) There were 1,700 gallons of water in the tank at 1:00 yesterday afternoon.

Since 500 gallons of water were added in the hour from noon to 1:00 pm, there were 1,700 - 500 = 1,200 gallons of water in the tank at noon, which is more than 1,000 gallons. Sufficient.

(2) There were 2,000 gallons of water in the tank at 3:00 yesterday afternoon.

If the 2,000 gallons mark was reached at 12:30 pm, meaning the water addition lasted only half an hour, then the initial amount in the tank was 2,000 - 1/2*500 = 1,750 gallons, more than 1,000 gallons. However, if the 2,000 gallons mark was reached at 3:00 pm, meaning the water addition lasted three hours, then the initial amount in the tank was 2,000 - 3*500 = 500 gallons, less than 1,000 gallons. Not sufficient.

Answer: A.
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Beginning at noon yesterday, water was added to a partially filled 24 Oct 2024, 02:34
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Bunuel, what if for Statement 2 said "there were 2000 gallons of water in the tank at 2:00 yesterday afternoon"

Given that the question asks for "MORE than 1000 gallons of water" and it could be exactly 1000 gallons at 12:00, then would it be also insufficient?

Thanks in advance!
Bunuel
guddo
Beginning at noon yesterday, water was added to a partially filled water tank at the constant rate of 500 gallons per hour. When there was a total of 2,000 gallons of water in the tank, no more was added. Was there more than 1,000 gallons of water in the tank at noon yesterday?

(1) There were 1,700 gallons of water in the tank at 1:00 yesterday afternoon.
(2) There were 2,000 gallons of water in the tank at 3:00 yesterday afternoon.

Show Spoiler
Attachment:
2023-12-19_17-44-06.png

Beginning at noon yesterday, water was added to a partially filled water tank at the constant rate of 500 gallons per hour. When there was a total of 2,000 gallons of water in the tank, no more was added. Was there more than 1,000 gallons of water in the tank at noon yesterday?

(1) There were 1,700 gallons of water in the tank at 1:00 yesterday afternoon.

Since 500 gallons of water were added in the hour from noon to 1:00 pm, there were 1,700 - 500 = 1,200 gallons of water in the tank at noon, which is more than 1,000 gallons. Sufficient.

(2) There were 2,000 gallons of water in the tank at 3:00 yesterday afternoon.

If the 2,000 gallons mark was reached at 12:30 pm, meaning the water addition lasted only half an hour, then the initial amount in the tank was 2,000 - 1/2*500 = 1,750 gallons, more than 1,000 gallons. However, if the 2,000 gallons mark was reached at 3:00 pm, meaning the water addition lasted three hours, then the initial amount in the tank was 2,000 - 3*500 = 500 gallons, less than 1,000 gallons. Not sufficient.

Answer: A.

If Statement 2 had said "there were 2000 gallons of water in the tank at 2:00 yesterday afternoon," it would still be insufficient. Here's why:

Since water was added at 500 gallons per hour starting from noon, if there were 2000 gallons at 2:00 pm, we know the tank was full by then. However, we don’t know exactly when it reached 2000 gallons. It could have been filled at 12:30 pm (which would mean that at noon there were 1,750 gallons, so more than 1000: answer YES), or it could have continued filling until 2:00 pm (which would mean there were exactly 1000 gallons at noon, so not more than 1000: answer NO).

Hope it's clear.
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