i believe it would be 5.25
12-5=7
7*12=84
84/ 16 = 5.25
i hope this helps
Complete question:
He amount of time that a customer spends waiting at an airport check-in counter is a random variable with mean 8.3 minutes and standard deviation 1.4 minutes. Suppose that a random sample of n equals 47 customers is observed. Find the probability that the average time waiting in line for these customers is
a) less than 8 minutes
b) between 8 and 9 minutes
c) less than 7.5 minutes
Answer:
a) 0.0708
b) 0.9291
c) 0.0000
Step-by-step explanation:
Given:
n = 47
u = 8.3 mins
s.d = 1.4 mins
a) Less than 8 minutes:

P(X' < 8) = P(Z< - 1.47)
Using the normal distribution table:
NORMSDIST(-1.47)
= 0.0708
b) between 8 and 9 minutes:
P(8< X' <9) =![[\frac{8-8.3}{1.4/ \sqrt{47}}< \frac{X'-u}{s.d/ \sqrt{n}} < \frac{9-8.3}{1.4/ \sqrt{47}}]](https://tex.z-dn.net/?f=%20%5B%5Cfrac%7B8-8.3%7D%7B1.4%2F%20%5Csqrt%7B47%7D%7D%3C%20%5Cfrac%7BX%27-u%7D%7Bs.d%2F%20%5Csqrt%7Bn%7D%7D%20%3C%20%5Cfrac%7B9-8.3%7D%7B1.4%2F%20%5Csqrt%7B47%7D%7D%5D)
= P(-1.47 <Z< 6.366)
= P( Z< 6.366) - P(Z< -1.47)
Using normal distribution table,

0.9999 - 0.0708
= 0.9291
c) Less than 7.5 minutes:
P(X'<7.5) = ![P [Z< \frac{7.5-8.3}{1.4/ \sqrt{47}}]](https://tex.z-dn.net/?f=%20P%20%5BZ%3C%20%5Cfrac%7B7.5-8.3%7D%7B1.4%2F%20%5Csqrt%7B47%7D%7D%5D%20)
P(X' < 7.5) = P(Z< -3.92)
NORMSDIST (-3.92)
= 0.0000
It takes about 14.55 years for quadruple your money
<em><u>Solution:</u></em>
Given that,
At 10 percent interest, how long does it take to quadruple your money
Rule of 144:
The Rule of 144 will tell you how long it will take an investment to quadruple
Here,
Rate of interest = 10 %
Therefore, number of years to quadruple your money is obtained by dividing 144 by 10
<em><u>Rule of 144 Formula: </u></em>

Where:
N = Number of many years times.
144 = Is the constant variable.
R = Rate of interest.

Thus it takes about 14.4 years for quadruple your money.
<em><u>Another method:</u></em>
If initial amount is $ 1 and it if quadruples it should be $ 4
We have to find the number of years if rate of interest is 10 %
Let "n" be the number of years
Then we can say,



Thus Option D 14.55 years is correct
N(75/100)=4.5 multiply both sides by 100
75n=450 divide both sides by 75
n=6cm