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
Answer: the amount a person pays for gas compared with the number of gallons purchased
Step-by-step explanation:
Answer:
The reference angle is 
Step-by-step explanation:
The given angle is
The reference angle is the acute angle, that a given angle makes with the x-axis.
First let us make a sketch of the given angle. <em>See diagram in attachment.</em>
Let
be the reference angle of 
Then, from the diagram, we need to subtract
from
to get to
.
We can therefore write the following equation and solve for
.

We group like terms to get,

We collect LCM to get,

We simplify to get,

We divide through by 
to get,
The correct answer is D.
since you have 11 cards and need to know how many red and black
r+b needs to equal 11
since r+b=11 isn't shown in any answer then none of them are correct, so none of the above