To calculate the percent change in David's water intake from Tuesday to Wednesday, we can use the following formula:
percent change = (new value - old value) / old value * 100
In this case, the old value is the number of cups of water David drank on Tuesday (16 cups) and the new value is the number of cups of water he drank on Wednesday (12 cups).
Plugging these values into the formula:
percent change = (12 - 16) / 16 * 100 = -25%
So David's water intake decreased by 25% from Tuesday to Wednesday.
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The original amount in the problem is the amount of water David drank on Tuesday, which is 16 cups.
It was given in the problem as the base value to calculate the percent change in David's water intake from Tuesday to Wednesday.
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The change in David's water intake in this problem is the difference between the amount of water he drank on Tuesday and the amount of water he drank on Wednesday.
On Tuesday, he drank 16 cups of water, and on Wednesday, he drank 12 cups of water.
So the change in David's water intake is:
16 cups - 12 cups = 4 cups
David drank 4 cups less water on Wednesday than on Tuesday.