Answer:
So then the correct answer would be:
B) .9996
Step-by-step explanation:
The exact way to solve this problem is using the binomial distribution, assuming that our random variable of interest is "number of students living in apartments" represented by X and 
And we want this probability:
![P(200 \leq X \leq 400) [tex]In order to find this probability we can use the foloowing excel code:"=BINOM.DIST(400,600,0.4,TRUE)-BINOM.DIST(199,600,0.4,TRUE)"And we got:[tex] P(200 \leq X \leq 400) =0.999675[tex]But for this case the problem says that we need to approximate, so then we can use the normal approximation to the normal distribution. We need to check the conditions in order to use the normal approximation. [tex]np=600*0.4=240\geq 10](https://tex.z-dn.net/?f=%20P%28200%20%5Cleq%20X%20%5Cleq%20400%29%20%5Btex%5D%3C%2Fp%3E%3Cp%3EIn%20order%20to%20find%20this%20probability%20we%20can%20use%20the%20foloowing%20excel%20code%3A%3C%2Fp%3E%3Cp%3E%22%3DBINOM.DIST%28400%2C600%2C0.4%2CTRUE%29-BINOM.DIST%28199%2C600%2C0.4%2CTRUE%29%22%3C%2Fp%3E%3Cp%3EAnd%20we%20got%3A%3C%2Fp%3E%3Cp%3E%5Btex%5D%20P%28200%20%5Cleq%20X%20%5Cleq%20400%29%20%3D0.999675%5Btex%5D%3C%2Fp%3E%3Cp%3EBut%20for%20this%20case%20the%20problem%20says%20that%20we%20need%20to%20approximate%2C%20so%20then%20we%20can%20use%20the%20normal%20approximation%20to%20the%20normal%20distribution.%20%3C%2Fp%3E%3Cp%3EWe%20need%20to%20check%20the%20conditions%20in%20order%20to%20use%20the%20normal%20approximation.%0A%3C%2Fp%3E%3Cp%3E%5Btex%5Dnp%3D600%2A0.4%3D240%5Cgeq%2010)
So we see that we satisfy the conditions and then we can apply the approximation.
If we appply the approximation the new mean and standard deviation are:
And then 
And we are interested on the following probability:
So then the correct answer would be:
B) .9996
Answer:
Step-by-step explanation:
Here is a list of possible outcomes.
Penny nickel
Heads heads
Heads tails
tails Heads
tails tails
Since there are four ways the two coins can land, the chances of getting tails - tails is 1 chance in 4.
8 hours. 125 - 5 = 120. 120 / 15 = 8. Kelly will need to tutor for 8 hours minimum to buy the dress.
Answer:
800 miles
Step-by-step explanation:
Let the number of miles be represented by x
Company A for $110 a day plus $0.80 per mile.
$110 + $0.80 × x
110 + 0.80x
Company B charges $30 a day plus $0.90 per mile to rent the same truck.
$30 + $0.90 × x
30 + 0.90x
110 + 0.80x = 30 + 0.90x
110 - 30 = 0.90x - 0.80x
80 = 0.1x
x = 80/0.1
x = 800 miles
800 miles driven per day makes the rental cost for Company A a better deal than Company B's
