Answer:
The original price of the item is $28.
Step-by-step explanation:
So to find the original price, we have to divide the sale price by the result of one minus the discount in percentage form.
So:
First convert 25% to a decimal, 0.25.
OP(original price) = 21 ÷ 1 - 0.25 =
1 - 0.25 = 0.75
21 ÷ 0.75 = 28.
(a) Average time to get to school
Average time (minutes) = Summation of the two means = mean time to walk to bus stop + mean time for the bust to get to school = 8+20 = 28 minutes
(b) Standard deviation of the whole trip to school
Standard deviation for the whole trip = Sqrt (Summation of variances)
Variance = Standard deviation ^2
Therefore,
Standard deviation for the whole trip = Sqrt (2^2+4^2) = Sqrt (20) = 4.47 minutes
(c) Probability that it will take more than 30 minutes to get to school
P(x>30) = 1-P(x=30)
Z(x=30) = (mean-30)/SD = (28-30)/4.47 ≈ -0.45
Now, P(x=30) = P(Z=-0.45) = 0.3264
Therefore,
P(X>30) = 1-P(X=30) = 1-0.3264 = 0.6736 = 67.36%
With actual average time to walk to the bus stop being 10 minutes;
(d) Average time to get to school
Actual average time to get to school = 10+20 = 30 minutes
(e) Standard deviation to get to school
Actual standard deviation = Previous standard deviation = 4.47 minutes. This is due to the fact that there are no changes with individual standard deviations.
(f) Probability that it will take more than 30 minutes to get to school
Z(x=30) = (mean - 30)/Sd = (30-30)/4.47 = 0/4.47 = 0
From Z table, P(x=30) = 0.5
And therefore, P(x>30) = 1- P(X=30) = 1- P(Z=0.0) = 1-0.5 = 0.5 = 50%
Answer:
Depends
Step-by-step explanation:
It depends because I don't know if I'm strong on the material you're asking about.
Answer:
The population of bacteria can be expressed as a function of number of days.
Population = ![\[5*2^{n-1}\]](https://tex.z-dn.net/?f=%5C%5B5%2A2%5E%7Bn-1%7D%5C%5D)
where n is the number of days since the beginning.
Step-by-step explanation:
Number of bacteria on the first day=![\[5 * 2^{0} = 5\]](https://tex.z-dn.net/?f=%5C%5B5%20%2A%202%5E%7B0%7D%20%3D%205%5C%5D)
Number of bacteria on the second day = ![\[5 * 2^{1} = 10\]](https://tex.z-dn.net/?f=%5C%5B5%20%2A%202%5E%7B1%7D%20%3D%2010%5C%5D)
Number of bacteria on the third day = ![\[5*2^{2} = 20\]](https://tex.z-dn.net/?f=%5C%5B5%2A2%5E%7B2%7D%20%3D%2020%5C%5D)
Number of bacteria on the fourth day = ![\[5*2^{3} = 40\]](https://tex.z-dn.net/?f=%5C%5B5%2A2%5E%7B3%7D%20%3D%2040%5C%5D)
As we can see , the number of bacteria on any given day is a function of the number of days n.
This expression can be expressed generally as where n is the number of days since the beginning.
