Calculus 1 : Rate

Study concepts, example questions & explanations for Calculus 1

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Example Questions

Example Question #2781 : Functions

The rate of growth of the number of bacterial cells in a dog bowl is proportional to the population. The population increased from 11300 to 28900 between 3:00 and 3:45. Determine the expected population at 5:15.

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of change of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value,   represents a measure of elapsed time relative to this population value, and  is the constant of proportionality.

Since the population increased from 11300 to 28900 between 3:00 and 3:45, we can solve for this constant of proportionality. Treat the minutes as decimals by dividing them by 60:

Now that the constant of proportionality is known, we can use it to find an expected population value relative to an initial population value due to the difference in time points:

Example Question #2782 : Functions

The rate of growth of the number of albatrosses plaguing wayward ships is proportional to the population. The population increased from 1123 to 1839 between 1798 and 1802. Determine the expected population in 1834.

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of change of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value,   represents a measure of elapsed time relative to this population value, and  is the constant of proportionality.

Since the population increased from 1123 to 1839 between 1798 and 1802, we can solve for this constant of proportionality:

Now that the constant of proportionality is known, we can use it to find an expected population value relative to an initial population value due to the difference in time points:

Example Question #91 : How To Find Constant Of Proportionality Of Rate

The rate of decrease of the number of living yeast cells as the bread is put into the oven is proportional to the population. The population decreased from 4,500,000,000 to 1,500,000 between 3:15 and 3:45. Determine the expected population at 4:15.

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of change of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value,   represents a measure of elapsed time relative to this population value, and  is the constant of proportionality.

Since the population decreased from 4,500,000,000 to 1,500,000 between 3:15 and 3:45, we can solve for this constant of proportionality. Convert minutes to decimals by dividing by 60:

Now that the constant of proportionality is known, we can use it to find an expected population value relative to an initial population value due to the difference in time points:

Example Question #2783 : Functions

The rate of decrease of the number of albino squirrels is proportional to the population. The population decreased from 413 to 136 between 2010 and 2015. Determine the expected population in 2018.

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of change of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value,   represents a measure of elapsed time relative to this population value, and  is the constant of proportionality.

Since the population decreased from 413 to 136 between 2010 and 2015, we can solve for this constant of proportionality:

Now that the constant of proportionality is known, we can use it to find an expected population value relative to an initial population value due to the difference in time points:

Example Question #2784 : Functions

The rate of decrease of the number of pollen particles in the air of a room with a vacuum on is proportional to the population. The population decreased from 12345 to 6789 between 3:00 and 4:00. Determine the expected population at 7:00.

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of change of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value,   represents a measure of elapsed time relative to this population value, and  is the constant of proportionality.

Since the population decreased from 12345 to 6789 between 3:00 and 4:00, we can solve for this constant of proportionality:

 

Now that the constant of proportionality is known, we can use it to find an expected population value relative to an initial population value due to the difference in time points:

Example Question #91 : How To Find Constant Of Proportionality Of Rate

The rate of decrease of the number of tunnel snakes is proportional to the population. The population decreased from 2445 to 813 between 2267 and 2269. Determine the expected population in 2277.

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of change of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value,   represents a measure of elapsed time relative to this population value, and  is the constant of proportionality.

Since the population decreased from 2445 to 813 between 2267 and 2269, we can solve for this constant of proportionality:

Now that the constant of proportionality is known, we can use it to find an expected population value relative to an initial population value due to the difference in time points:

Example Question #101 : Constant Of Proportionality

The rate of decrease of the number of baceterium due to an introduction of soap is proportional to the population. The population decreased from 15800 to 2400 between 3:00 and 5:00. Determine the expected population at 5:30.

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of change of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value,   represents a measure of elapsed time relative to this population value, and  is the constant of proportionality.

Since the population decreased from 15800 to 2400 between 3:00 and 5:00, we can solve for this constant of proportionality:

Now that the constant of proportionality is known, we can use it to find an expected population value relative to an initial population value due to the difference in time points. Convert minutes to decimals by dividing by 60:

Example Question #102 : Constant Of Proportionality

The rate of decrease of the number of black lotuses is proportional to the population. The population decreased from 1100 to 85 between 1993 and 2013. Determine the expected population in 2015.

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of change of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value,   represents a measure of elapsed time relative to this population value, and  is the constant of proportionality.

Since the population decreased from 1100 to 85 between 1993 and 2013, we can solve for this constant of proportionality:

Now that the constant of proportionality is known, we can use it to find an expected population value relative to an initial population value due to the difference in time points:

Example Question #103 : Constant Of Proportionality

The rate of growth of the number of tree frogs is proportional to the population. The population increased from 43800 to 87215 between 1990 and 1995. Determine the expected population in 2015.

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of change of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value,   represents a measure of elapsed time relative to this population value, and  is the constant of proportionality.

Since the population increased from 43800 to 87215 between 1990 and 1995, we can solve for this constant of proportionality:

Now that the constant of proportionality is known, we can use it to find an expected population value relative to an initial population value due to the difference in time points:

Example Question #104 : Constant Of Proportionality

The rate of growth of the number of glowing mushrooms in a flooded cave is proportional to the population. The population increased from 110 to 310 between January and July. Determine the expected population in October.

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of change of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value,   represents a measure of elapsed time relative to this population value, and  is the constant of proportionality.

Since the population increased from 110 to 310 between January and July, we can solve for this constant of proportionality. Use the number of the months as they're ordered in the calendar:

Now that the constant of proportionality is known, we can use it to find an expected population value relative to an initial population value due to the difference in time points:

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