# Applications of exponentials

There are many real world applications that require exponents. For example, exponentials are used to determine population growth and they are also used in finance to calculate different types of interest.

Example 1:

A type of bacteria has a very high exponential growth rate at 80% every hour. If there are 10 bacteria, determine how many there will be in five hours, in one day and in one week?

Solution:

# Step 1: Exponential formula

final population = initial population x (1 + growth percentage)time period in hours

Therefore, in this case:

final population = 10 (1,8)n

where n = number of hours.

Step 2: In 5 hours

final population = 10 (1,8)5 $\approx 189$

Step 3: In 1 day = 24 hours

final population = 10 (1,8)24 $\approx$ 13 382 588

Step 4: In 1 week = 168 hours

final population = 10 (1,8)168 $\approx$ 7,687 x 1043

Note this answer is given in scientific notation as it is a very big number.

Also Read : How to Merging of Exponents and Roots

Example 2:

A species of extremely rare deep water fish has a very long lifespan and rarely has offspring. If there are a total of 821 of this type of fish and their growth rate is 2% each month, how many will there be in half of a year? What will the population be in ten years and in one hundred years?

Solution:

Step 1: Exponential formula

final population = initial population x (1 + growth percentage)time period in months

Therefore, in this case:

final population = 821(1,02)n

where n = number of months.

Step 2: In half a year = 6 months

final population = 821(1,02)6 $\approx 925$

Step 3: In 10 years = 120 months

final population = 821(1,02)120 $\approx$ 8838

Step 4: In 100 years = 1200 months

final population = 821(1,02)1200 $\approx$ 1,716 x 1013

Note: this answer is also given in scientific notation as it is a very big number.

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