Solve a problem of your own!
Download the Studdy App!

Math

Math Snap

PROBLEM

A study is done on the number of bacteria cells in a petri dish. Suppose that the population size P(t)P(t) after tt hours is given by the following exponential function.
P(t)=2500(0.82)tP(t)=2500(0.82)^{t} Find the initial population size.
25002500 Does the function represent growth or decay?
growth
decay
By what percent does the population size change each hour?
\square \%
Explanation
Check

STEP 1

1. The function P(t)=2500(0.82)t P(t) = 2500(0.82)^t represents the population size of bacteria after t t hours.
2. We need to determine the initial population size, whether the function represents growth or decay, and the percent change per hour.

STEP 2

1. Determine the initial population size.
2. Determine if the function represents growth or decay.
3. Calculate the percent change per hour.

STEP 3

The initial population size is the value of P(t) P(t) when t=0 t = 0 .
Substitute t=0 t = 0 into the function:
P(0)=2500(0.82)0 P(0) = 2500(0.82)^0 Since any number to the power of zero is 1:
P(0)=2500×1=2500 P(0) = 2500 \times 1 = 2500 The initial population size is 2500 2500 .

STEP 4

To determine if the function represents growth or decay, examine the base of the exponential function, which is 0.82 0.82 .
Since 0.82<1 0.82 < 1 , the function represents decay.

SOLUTION

To find the percent change per hour, calculate the difference between the base and 1, and then convert it to a percentage.
The base is 0.82 0.82 , so the change is:
10.82=0.18 1 - 0.82 = 0.18 Convert 0.18 0.18 to a percentage:
0.18×100%=18% 0.18 \times 100\% = 18\% The population size decreases by 18% 18\% each hour.
The initial population size is 2500 2500 , the function represents decay, and the population size decreases by 18% 18\% each hour.

Was this helpful?
banner

Start understanding anything

Get started now for free.

OverviewParentsContactPolicyTerms
TwitterInstagramFacebookTikTokDiscord