Salutations!
Let the number be
![x](https://tex.z-dn.net/?f=x)
The equation would be:
![x+20=18](https://tex.z-dn.net/?f=x%2B20%3D18)
Lets solve this!
We need to always keep the variables aside, and the numbers aside.
![x=20-18](https://tex.z-dn.net/?f=x%3D20-18)
![x=2](https://tex.z-dn.net/?f=x%3D2)
Hope I helped (:
Have a great day!
Answer:
3 minutes
Step-by-step explanation:
It says that the number of bacteria reduces by half every minute.
So we can represent this situation by the equation:
![x=x_{0}*(\frac{1}{2})^{n}](https://tex.z-dn.net/?f=x%3Dx_%7B0%7D%2A%28%5Cfrac%7B1%7D%7B2%7D%29%5E%7Bn%7D)
where x₀ is the original number of bacteria and x is the number of bacteria that remains after n minutes.
Plugin x₀ = 3000 and x = 375 into the above formula
![375=3000*(\frac{1}{2} )^{n}](https://tex.z-dn.net/?f=375%3D3000%2A%28%5Cfrac%7B1%7D%7B2%7D%20%29%5E%7Bn%7D)
Dividing both sides by 3000
![\frac{375}{3000}=\frac{3000}{3000}*(\frac{1}{2} )^{n}](https://tex.z-dn.net/?f=%5Cfrac%7B375%7D%7B3000%7D%3D%5Cfrac%7B3000%7D%7B3000%7D%2A%28%5Cfrac%7B1%7D%7B2%7D%20%29%5E%7Bn%7D)
Cancel out 3000's on the top and bottom of the right side
![\frac{375}{3000}=(\frac{1}{2} )^{n}](https://tex.z-dn.net/?f=%5Cfrac%7B375%7D%7B3000%7D%3D%28%5Cfrac%7B1%7D%7B2%7D%20%29%5E%7Bn%7D)
Simplifying the fraction ![\frac{375}{3000}](https://tex.z-dn.net/?f=%5Cfrac%7B375%7D%7B3000%7D)
![\frac{1}{8}=(\frac{1}{2} )^{n}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B8%7D%3D%28%5Cfrac%7B1%7D%7B2%7D%20%29%5E%7Bn%7D)
![\frac{1}{2}*\frac{1}{2}*\frac{1}{2}=(\frac{1}{2} )^{n}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%2A%5Cfrac%7B1%7D%7B2%7D%2A%5Cfrac%7B1%7D%7B2%7D%3D%28%5Cfrac%7B1%7D%7B2%7D%20%29%5E%7Bn%7D)
![(\frac{1}{2} )^{3}=(\frac{1}{2} )^{n}](https://tex.z-dn.net/?f=%28%5Cfrac%7B1%7D%7B2%7D%20%29%5E%7B3%7D%3D%28%5Cfrac%7B1%7D%7B2%7D%20%29%5E%7Bn%7D)
Comparing the exponents on both sides, we get
n=3
So, it will take 3 minutes for to reduce the number of bacteria from 3000 to 375.
Answer:
54
Step-by-step explanation:
you can use a proportion to solve:
6/3=x/27
3x=27x6
3x=162
x=54
In this situation, it is similar to a coin flip, so think about flipping a 2 sided chip, one side colored yellow the other blue, flipping the chip will result in a 50/50 chance for it to land on either side, so no matter how many times you flip it it will always be a 1/2 chance of it being on one of the sides