Answer:
Step-by-step explanation:
Given
Equations are
and 
take 

Put the value of y in another equation

Put the value of x in y

Hence,
15x+100=28
x=-6/5
The answer is -6/5
Answer:
Step-by-step explanation:
Since population std deviation is not known, we use t critical value for testing of hypothesis.
a) 90% conf level when n =28
df = 27, t critical = 1.706
b) 95% 28
df =27 and t critical = 2.052
c) 90% and 15
df =14 and t critical = 1.761
d) 95% and n =15
df =14: t critical = 2.145
Simply divide with your calculator
18049/14 ≈ 1289.214
≈ 1289.214
<span>25.7 years
The rule of 72 is a simple approximation on how long it will take to double your money. You simply divide 72 by the interest rate and you'll have your estimate on the number of years it will take. So
72 / 2.8 = 25.7 years.
To demonstrate that it's just an estimate, you can take the log of 2 and divide by the log of 1.028 to get the exact value. This far more complicated calculation gives the result of 25.1 years. And to be honest, the estimate of 25.7 years is more than close enough for such an quick and easy rule of thumb.</span>