Answer:
x=9 x=-1
Step-by-step explanation:
x²-8x-9=0 a=1 b=-8 c=-9
you have to use the quadratic formula to get the values.
Answer:
No, the on-time rate of 74% is not correct.
Solution:
As per the question:
Sample size, n = 60
The proportion of the population, P' = 74% = 0.74
q' = 1 - 0.74 = 0.26
We need to find the probability that out of 60 trains, 38 or lesser trains arrive on time.
Now,
The proportion of the given sample, p = 
Therefore, the probability is given by:
![P(p\leq 0.634) = [\frac{p - P'}{\sqrt{\frac{P'q'}{n}}}]\leq [\frac{0.634 - 0.74}{\sqrt{\frac{0.74\times 0.26}{60}}}]](https://tex.z-dn.net/?f=P%28p%5Cleq%200.634%29%20%3D%20%5B%5Cfrac%7Bp%20-%20P%27%7D%7B%5Csqrt%7B%5Cfrac%7BP%27q%27%7D%7Bn%7D%7D%7D%5D%5Cleq%20%5B%5Cfrac%7B0.634%20-%200.74%7D%7B%5Csqrt%7B%5Cfrac%7B0.74%5Ctimes%200.26%7D%7B60%7D%7D%7D%5D)
P![(p\leq 0.634) = P[z\leq -1.87188]](https://tex.z-dn.net/?f=%28p%5Cleq%200.634%29%20%3D%20P%5Bz%5Cleq%20-1.87188%5D)
P![(p\leq 0.634) = P[z\leq -1.87] = 0.0298](https://tex.z-dn.net/?f=%28p%5Cleq%200.634%29%20%3D%20P%5Bz%5Cleq%20-1.87%5D%20%3D%200.0298)
Therefore, Probability of the 38 or lesser trains out of 60 trains to be on time is 0.0298 or 2.98 %
Thus the on-time rate of 74% is incorrect.
Answer: the value of the account after 6 years is $101559.96
Step-by-step explanation:
If $64,000 is invested in an IRA account, then
Principal = $64,000
So P = 64,000
The rate at which $64000 was compounded is 8%
So r = 8/100 = 0.08
If it is compounded once in a year, this means that it is compounded annually (and not semi annually, quarterly or others). So
n = 1
We want to determine the value of the account after 6 years, this means
time, t = 6
Applying the compound interest formula,
A = P(1 + r/n)^nt
A = amount after n number of years
A = 64000( 1 + 0.08/1)^1×6
A = 64000(1.08)^6
A= 64000×1.58687432294
A= 101559.956668416
Approximately $101559.96 to 2 decimal places
If you recall soh-cah-toa, tangent is equal to the opposite length divided by the adjacent length so it is true.