A scientist counts 35 bacteria present in a culture and finds that the number of bacteria triples each hour. The function y = 35 • 3x models the number of bacteria after x hours.

Graph the function. (You do not need to submit the graph).

Use the graph to estimate when there will be about 550 bacteria in the culture.

Question

A scientist counts 35 bacteria present in a culture and finds that the number of bacteria triples each hour. The function y = 35 • 3x models the number of bacteria after x hours.

Graph the function. (You do not need to submit the graph).

Use the graph to estimate when there will be about 550 bacteria in the culture.

anonymous · Answer

550=35×3x
 divided by 35 we get 
110/7=3x
change of base get 
ln(110/7)ln(3)
2.5 hours

campbell_st · Answer

so is the equation 

$$y = 35 \times 3^x$$

anonymous · Answer

yea

campbell_st · Answer

ok... so to graph the equation substitute some values 

x = 0, 1, 2, 3, 5, 10

which will give you some y values

plot them 

or use some graphing software. 

you need to graph as you're asked to estimate from the graph... 

so when you have graphed it look at 550.. 

the graph is exponential... so looks a bit like 

|dw:1365712487691:dw|

anonymous · Answer

i wanted to know am i missing any step in my answer

anonymous · Answer

yes, it looks like you are missing the step between 110/7=3x and using the change of base, the step where you use log (base 3) on both sides to get $$\log_3 (110/7)=x$$