Answer:
There will be 50 bacteria remaining after 28 minutes.
Step-by-step explanation:
The exponential decay equation is

N= Number of bacteria after t minutes.
= Initial number of bacteria when t=0.
r= Rate of decay per minute
t= time is in minute.
The sample begins with 500 bacteria and after 11 minutes there are 200 bacteria.
N=200
= 500
t=11 minutes
r=?



Taking ln both sides



To find the time when there will be 50 bacteria remaining, we plug N=50,
= 500 and
in exponential decay equation.


Taking ln both sides




minutes
There will be 50 bacteria remaining after 28 minutes.
Answer:
x = -9
Step-by-step explanation:
12 + 2x + 24 = 27 + x
(12 + 24) + 2x = 27 + x
36 + 2x = 27 + x
subtract 27 from both sides
36-27 + 2x = 27-27 + x
9 + 2x = x
subtract x from both sides
9 + x = 0
subtract 9 from both sides
x = -9
(the steps could've been faster but that shows the most work)
check:
12 + 2(-9) + 24 = 27 + (-9)
36 - 18 = 18
18 = 18
True!
so -9 is correct
Answer:
Step-by-step explanation:
7. 1/4 of 84 is 21, then 1/3 of that is 7
Answer:
Girls in Mr. Chang's class: 28 - 21 ; # girl students = # total students - # boy students ; 7 girl students.
Boys in Mr. Chang's class: 28 - 7 ; # boy students = # total students - girl students ; 21 boy students.
Question: Rosana building a chicken coop at the bottom of your residencia used 4 gallons for the transport of the material. One of gallons was fragile and not make it. What gallon not stand it? (a) the water
(b) the mass of c the brita
(d) the sand Answer: B) the mass of c the brita