Alright, so you have the basic formula- good.
You have the A value (400), the interest rate r (7.5% -> .075 in decimal), and the final P value (8500). So, we only need to solve for t.
8500 = (400)(1+.075)^t
/400 /400
21.25 = 1.075^t
logarithms are the inverse of exponents, basically, if you have an example like
y = b^x, then a logarithm inverts it, logy(baseb)=x
Makes sense if you consider a power of ten.
1000 = 10^3
if you put logbase10(1000), you'll get 3.
Anyways, though, to solve the problem make a log with a base of 1.075 in your calculator
log21.25(base 1.075) = t
also, because of rules of change of base (might want to look this up to clarify), you can write this as log(21.25)/log(1.075) = t
Thus, t is 42.26118551.
Rounded to hundredths, t=42.26
Because if the number was rational then we can tell by looking at the numbers. The rational number should be one number or a repeating decimal or terminating number. plus because if a number was like this 5.7696... that means its irrational because we dont know the end of the number. The rational numbers are terminating numbers or either decimal or repeating numbers because we know the end of those numbers.
Answer:
Step 4, x = 3
Step-by-step explanation:
Step 4 was wrong, instead of 6x = 6, it should be 6x = 18. They shoudl've added 6 to both sides instead of subtracting 6 as ur trying to cancel out the 6 on the left side of the equation. So:
6x = 18
x = 3
Answer:
538 books should be tested.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
How many books should be tested to estimate the average force required to break the binding to within 0.08 lb with 99% confidence?
n books should be tested.
n is found when 
We have that 
Rounding up
538 books should be tested.
