1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
chubhunter [2.5K]
3 years ago
12

8. It took Sharon 85 minutes to wash three cars. She spent x minutes on each car and 10 minutes

Mathematics
1 answer:
Yuliya22 [10]3 years ago
8 0

Answer:

c. 25 minutes

Step-by-step explanation:

3x + 10 = 85

3x = 85 - 10

3x = 75

x = 25

You might be interested in
2,17,82,257,626,1297 next one please ?​
In-s [12.5K]

The easy thing to do is notice that 1^4 = 1, 2^4 = 16, 3^4 = 81, and so on, so the sequence follows the rule n^4+1. The next number would then be fourth power of 7 plus 1, or 2402.

And the harder way: Denote the <em>n</em>-th term in this sequence by a_n, and denote the given sequence by \{a_n\}_{n\ge1}.

Let b_n denote the <em>n</em>-th term in the sequence of forward differences of \{a_n\}, defined by

b_n=a_{n+1}-a_n

for <em>n</em> ≥ 1. That is, \{b_n\} is the sequence with

b_1=a_2-a_1=17-2=15

b_2=a_3-a_2=82-17=65

b_3=a_4-a_3=175

b_4=a_5-a_4=369

b_5=a_6-a_5=671

and so on.

Next, let c_n denote the <em>n</em>-th term of the differences of \{b_n\}, i.e. for <em>n</em> ≥ 1,

c_n=b_{n+1}-b_n

so that

c_1=b_2-b_1=65-15=50

c_2=110

c_3=194

c_4=302

etc.

Again: let d_n denote the <em>n</em>-th difference of \{c_n\}:

d_n=c_{n+1}-c_n

d_1=c_2-c_1=60

d_2=84

d_3=108

etc.

One more time: let e_n denote the <em>n</em>-th difference of \{d_n\}:

e_n=d_{n+1}-d_n

e_1=d_2-d_1=24

e_2=24

etc.

The fact that these last differences are constant is a good sign that e_n=24 for all <em>n</em> ≥ 1. Assuming this, we would see that \{d_n\} is an arithmetic sequence given recursively by

\begin{cases}d_1=60\\d_{n+1}=d_n+24&\text{for }n>1\end{cases}

and we can easily find the explicit rule:

d_2=d_1+24

d_3=d_2+24=d_1+24\cdot2

d_4=d_3+24=d_1+24\cdot3

and so on, up to

d_n=d_1+24(n-1)

d_n=24n+36

Use the same strategy to find a closed form for \{c_n\}, then for \{b_n\}, and finally \{a_n\}.

\begin{cases}c_1=50\\c_{n+1}=c_n+24n+36&\text{for }n>1\end{cases}

c_2=c_1+24\cdot1+36

c_3=c_2+24\cdot2+36=c_1+24(1+2)+36\cdot2

c_4=c_3+24\cdot3+36=c_1+24(1+2+3)+36\cdot3

and so on, up to

c_n=c_1+24(1+2+3+\cdots+(n-1))+36(n-1)

Recall the formula for the sum of consecutive integers:

1+2+3+\cdots+n=\displaystyle\sum_{k=1}^nk=\frac{n(n+1)}2

\implies c_n=c_1+\dfrac{24(n-1)n}2+36(n-1)

\implies c_n=12n^2+24n+14

\begin{cases}b_1=15\\b_{n+1}=b_n+12n^2+24n+14&\text{for }n>1\end{cases}

b_2=b_1+12\cdot1^2+24\cdot1+14

b_3=b_2+12\cdot2^2+24\cdot2+14=b_1+12(1^2+2^2)+24(1+2)+14\cdot2

b_4=b_3+12\cdot3^2+24\cdot3+14=b_1+12(1^2+2^2+3^2)+24(1+2+3)+14\cdot3

and so on, up to

b_n=b_1+12(1^2+2^2+3^2+\cdots+(n-1)^2)+24(1+2+3+\cdots+(n-1))+14(n-1)

Recall the formula for the sum of squares of consecutive integers:

1^2+2^2+3^2+\cdots+n^2=\displaystyle\sum_{k=1}^nk^2=\frac{n(n+1)(2n+1)}6

\implies b_n=15+\dfrac{12(n-1)n(2(n-1)+1)}6+\dfrac{24(n-1)n}2+14(n-1)

\implies b_n=4n^3+6n^2+4n+1

\begin{cases}a_1=2\\a_{n+1}=a_n+4n^3+6n^2+4n+1&\text{for }n>1\end{cases}

a_2=a_1+4\cdot1^3+6\cdot1^2+4\cdot1+1

a_3=a_2+4(1^3+2^3)+6(1^2+2^2)+4(1+2)+1\cdot2

a_4=a_3+4(1^3+2^3+3^3)+6(1^2+2^2+3^2)+4(1+2+3)+1\cdot3

\implies a_n=a_1+4\displaystyle\sum_{k=1}^3k^3+6\sum_{k=1}^3k^2+4\sum_{k=1}^3k+\sum_{k=1}^{n-1}1

\displaystyle\sum_{k=1}^nk^3=\frac{n^2(n+1)^2}4

\implies a_n=2+\dfrac{4(n-1)^2n^2}4+\dfrac{6(n-1)n(2n)}6+\dfrac{4(n-1)n}2+(n-1)

\implies a_n=n^4+1

4 0
3 years ago
Hey answer this pls!!​
Kitty [74]

Answer:

That would be A) -3/5.

Step-by-step explanation:

Here it is.

6 0
2 years ago
You have decided to purchase a car for $22,346. 16. The credit union requires a 10% down payment and will finance the balance wi
Natali [406]

The amount that the credit union will finance is $24169.60

We have given that the cost of the car is $22,346. 16

and the credit union required 10% down payment

and sale tax=7.6%

The license and title charges are $125. 13.

We have to determine that the  amount that the credit union will

finance Now  we have sale tax 7.6% for $22,346. 16

Therefore, we get

\frac{7.6}{100} \times 22,346. 16=1698.31

<h3>What is the amount that the credit union finance ?</h3>

credit union finance=cost of car+sales tax+the license and title  charges.

=22346.16+1698.31+12.13\\=24169.60

Therefore, the amount that the credit union will finance is $24169.60

To learn more about the credit union will finance visit:

brainly.com/question/15641576

4 0
2 years ago
How many solutions does the equation below have?
miskamm [114]

Answer:

1. none

Step-by-step explanation:

When you simplify the expression, you see that the statement is is false for any value of x.

7 0
3 years ago
Read 2 more answers
A 2-month membership to the gym costs $125. Jim would like to be a member for 8 months. What is the total amount he will pay for
ArbitrLikvidat [17]
125/2=66.5•8= 532 hope this helps
5 0
3 years ago
Read 2 more answers
Other questions:
  • Robert invests $3,250 into a money market account with an annual 1.7% simple interest rate. If he does not add or subtract any m
    8·1 answer
  • What is the greatest common factor of 3x^2-9x
    11·1 answer
  • Three students share 5 peaches equally. How many peaches does each student get?
    10·2 answers
  • Cecilia's train travled at 240 miles in 3 hours. How far will it travel in 5.5 hours.
    9·1 answer
  • Find the value of y.
    15·1 answer
  • Wilma can mow a lawn in 3 hours. If Kyle helps her with another mower, the lawn can be mowed in 2 hours. how long would it take
    14·1 answer
  • It is known that the distance in metres through which a body falls freely varies directly as the square of the time taken. If a
    10·1 answer
  • Uma pipa é presa a um fio esticada que forma um ângulo de 45c com o solo. O comprimento do dia é 80m. Determine a altura da pipa
    9·1 answer
  • Find the volume of the rectangle in the picture
    15·1 answer
  • Randy is starting a beehive so that he can have fresh
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!