12/84 = 1/7 ≈ 0.14
The discount rate was 14%
Answer:
In the pic
Step-by-step explanation:
If you have any questions about the way I solved it, don't hesitate to ask me in the comments below =)
Exponential growth functions are the functions that normally take the form
y=ab^x
where:
a=initial value
b=growth rate
x=time
An example of situation that takes this form is the population growth of a particular group say and organism.
6. One variable only so pretty straightforward.
length-x+4
width-x
x+x+4=80
2x=76
x=38
x+4=42
answer: length 42cm and width 38cm
7. Another money problem!
n-# of nickels
q-# of quarters
n=3+q
0.05n+0.25q=2.85
Substitution works like a charm!
0.05(3+q)+0.25q=2.85
0.15+0.05q+0.25q=2.85
0.3q=2.7
q=9
n=3+q
n=3+9
n=12
answer: 9 nickels and 12 quarters
8. One variable situation again.
Ann's money-2b+9
Betty's money-b
b+2b+9=60
3b=51
b=17
2b+9=43
answer: Ann has $43 and Betty has $17.
9. # of red m&m's-x+1
# of blue m&m's-x
x+1+x=13
x=6
x+1=7
answer: 6 blue and 7 red m&m's
10. a-number of adult tickets
s-number of student tickets
a+s=785 ----> a=785-s
5a+2s=3280
5(785-s)+2s=3280
-3s=-645
s=215
a+s=785
a+215=785
a=570
answer: 215 children tickets and 570 adult tickets
Answer:
Step-by-step explanation:
The sum you are trying to understand is this.
Remember that in general when you have a geometric series
you have that
and that equality is true as long as 
.
Therefore here we have
and 
Therefore we can use the formula and
