,Score 19/22
You passed this Milestone
19 questions were answered correctly.
3UNIT 5 — MILESTONE 5 questions were answered incorrectly.
1
Susan monitors the number of strep infections reported in a certain neighborhood in a given week. The recent
numbers are shown in this table:
Week Number of People
0 20
1 26
2 34
3 44
According to her reports, the reported infections are growing at a rate of 30%.
If the number of infections continues to grow exponentially, what will the number of infections be in week
10?
203 people
206 people
276 people
, 297 people
RATIONALE
In general, exponential growth is modeled using this equation. We will use information from
the problem to find values to plug into this equation.
The initial number of infections is , so this is the value for a. The infection rate is ,
so this is our value for b (remember to write it as a decimal). We want to know how many
infections there will be in week 10, so we will use for the value for x. We will need to . Start by
solve for y simplifying what's inside the parentheses.
1 plus is . Next, take this value to the
power of .
to the power of is
There will be 276 people infected in week 10. . Finally, multiply this by .
CONCEPT
Exponential Growth 2
and
Suppose .
Find the value of .
RATIONALE
To evaluate this composite function, focus on the innermost function first. Evaluate
first by plugging in for the variable x in the function .
, Once x has been replaced with , evaluate the expression.
The function
evaluates to . To evaluate , use the value of , which
is
, as the input for the function f left parenthesis x right
Once parenthesis.
x has been replaced with , evaluate the
expression.
This tells us that is equal to .
CONCEPT
Function of a Function 3
Write the following as a single rational expression.
RATIONALE
Just as with numeric fractions, we can re-write division of algebraic fractions as multiplication and
multiply across numerators and denominators. To re-write fraction division as multiplication, re-
write the second fraction as its reciprocal (flipping the numerator and denominator).
You passed this Milestone
19 questions were answered correctly.
3UNIT 5 — MILESTONE 5 questions were answered incorrectly.
1
Susan monitors the number of strep infections reported in a certain neighborhood in a given week. The recent
numbers are shown in this table:
Week Number of People
0 20
1 26
2 34
3 44
According to her reports, the reported infections are growing at a rate of 30%.
If the number of infections continues to grow exponentially, what will the number of infections be in week
10?
203 people
206 people
276 people
, 297 people
RATIONALE
In general, exponential growth is modeled using this equation. We will use information from
the problem to find values to plug into this equation.
The initial number of infections is , so this is the value for a. The infection rate is ,
so this is our value for b (remember to write it as a decimal). We want to know how many
infections there will be in week 10, so we will use for the value for x. We will need to . Start by
solve for y simplifying what's inside the parentheses.
1 plus is . Next, take this value to the
power of .
to the power of is
There will be 276 people infected in week 10. . Finally, multiply this by .
CONCEPT
Exponential Growth 2
and
Suppose .
Find the value of .
RATIONALE
To evaluate this composite function, focus on the innermost function first. Evaluate
first by plugging in for the variable x in the function .
, Once x has been replaced with , evaluate the expression.
The function
evaluates to . To evaluate , use the value of , which
is
, as the input for the function f left parenthesis x right
Once parenthesis.
x has been replaced with , evaluate the
expression.
This tells us that is equal to .
CONCEPT
Function of a Function 3
Write the following as a single rational expression.
RATIONALE
Just as with numeric fractions, we can re-write division of algebraic fractions as multiplication and
multiply across numerators and denominators. To re-write fraction division as multiplication, re-
write the second fraction as its reciprocal (flipping the numerator and denominator).
