The amount of gasoline stored at a fuel station is decreasing at a rate of r(t) liters per hour (where t is the time in hours).What does ∫2021r(t)dt=−450 mean?Choose 1 answer:(A) During the 20th hour, the amount of gasoline at the fuel station decreased by 450 liters.(B) During the first 20 hours, the amount of gasoline at the fuel station decreased by 450 liters.(C) During the first 21 hours, the amount of gasoline at the fuel station decreased by 450 liters.(D) During the 21st hour, the amount of gasoline at the fuel station decreased by 450 liters.
Q. The amount of gasoline stored at a fuel station is decreasing at a rate of r(t) liters per hour (where t is the time in hours).What does ∫2021r(t)dt=−450 mean?Choose 1 answer:(A) During the 20th hour, the amount of gasoline at the fuel station decreased by 450 liters.(B) During the first 20 hours, the amount of gasoline at the fuel station decreased by 450 liters.(C) During the first 21 hours, the amount of gasoline at the fuel station decreased by 450 liters.(D) During the 21st hour, the amount of gasoline at the fuel station decreased by 450 liters.
Understand expression: Understand the integral expression.The integral expression ∫2021r(t)dt represents the total change in the amount of gasoline at the fuel station from hour 20 to hour 21.
Interpret negative sign: Interpret the negative sign. The negative sign in front of 450 indicates that the amount of gasoline is decreasing. Therefore, the integral tells us that there is a decrease in the amount of gasoline.
Determine time interval: Determine the time interval.The integral limits are from 20 to 21, which means we are looking at the change during the 21st hour, not the cumulative change over the first 20 or 21 hours.
Match interpretation: Match the interpretation with the answer choices.The correct interpretation is that during the 21st hour, the amount of gasoline at the fuel station decreased by 450 liters. This matches with choice (D).
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