Question

Fred placed 3 strands of bacteria in a petri dish. The bacteria strands double every hour. Write a formula to represent how many bacteria strands are present at the nth hour. Then, use the formula to determine how many strands of bacteria are present at 4 hours.

Which is correct:
A. f(n) = 3(2)n; 59 strands of bacteria
B. f(n) = 2(3)n; 82 strands of bacteria
C. f(n) = 3(2)n; 48 strands of bacteria
D. f(n) = 2(3)n; 162 strands of bacteria

Answer 1

f(n) = 3(2)n; 48 strands of bacteria

Explanation:

Answer 2

C.
`f(n) = 3(2)^n` ; 48 strands of bacteria

Explanation:

Fred placed 3 strands of bacteria in a petri dish.

The bacteria strands double every hour.

Formula : y = ab^x

Where a is the initial value

b = growth rate

x = hours

So, A formula to represent how many bacteria strands are present at the nth hour :
`f(n)=3(2)^n`

Now we are supposed to find how many strands of bacteria are present at 4 hours.

Substitute the value in the formula :

`f(4)=3(2)^(4)`

f(4)=48

Hence 48 strands of bacteria are present at 4 hours.