answer.
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
cestrela7 [59]
2 years ago
5

Mike has coffee worth $4 per pound that he wishes to mix with 20 pounds of coffee worth $7 per pound to get a mixture that can b

e sold for $5 per pound. How many pounds of the cheaper coffee should he use?
Mathematics
1 answer:
Alinara [238K]2 years ago
5 0
\bf \begin{array}{lccclll}
&\stackrel{lbs}{amount}&\stackrel{per~lb}{price}&\stackrel{amount}{price}\\
&------&------&------\\
\textit{\$4/lb coffee}&x&4&4x\\
\textit{\$7/lb coffee}&20&7&140\\
------&------&------&------\\
mixture&y&5&5y
\end{array}

so, we know the mixture is the sum of both types of coffee, thus x + 20 = y, and 4x + 140 = 5y.

\bf \begin{cases}
x+20=\boxed{y}\\
4x+140=5y\\
----------\\
4x+140=5\left( \boxed{x+20} \right)
\end{cases}
\\\\\\
4x+140=5x+100\implies 140-100=5x-4x\implies 40=x
You might be interested in
Suppose a1=12−12,a2=23−13,a3=34−14,a4=45−15,a5=56−16. a) Find an explicit formula for an: . b) Determine whether the sequence is
lorasvet [3.4K]

I'm going to assume you meant to write fractions (because if a_n are all non-negative integers, the series would clearly diverge), so that

a_1=\dfrac12-\dfrac12

a_2=\dfrac23-\dfrac13

a_3=\dfrac34-\dfrac14

and so on.

a. If the pattern continues as above, we would have the general term

a_n=\dfrac n{n+1}-\dfrac1{n+1}=\dfrac{n-1}{n+1}

b. Note that we can write a_n as

a_n=\dfrac{n-1}{n+1}=\dfrac{n+1-2}{n+1}=1-\dfrac2{n+1}

The series diverges by comparison to the divergent series

\displaystyle\sum_{n=1}^\infty\frac1n

4 0
2 years ago
Simplify the following expression, if you can see the picture the expression is as follows:
Kobotan [32]
\sqrt{40}=2 \sqrt{10} and \sqrt{90} = 3\sqrt{10}, so we have \sqrt{10}(2-1+3). which is 4 \sqrt{10}.
8 0
2 years ago
The following data represent the length of life in
Natali [406]

Answer:

(a) For the stem-and-leaf plot, we need to organise all data in columns, one column is the stem and a second column is the leaf, but in this case, stems are going to be the digits to the left of the decimal point, and leafs are the digits to the right of the decimal point:

<u>Stem</u>            <u> Leaf </u>

0             2 2 2 3 3 4 5 7

1              0 2 3 5 5 8

2             0 3 5

3             0 3

4             0 5 7

5             0 5 6 9

6             0 0 0 5

(b) Relative frequency distribution.

Remember that, a relative frequency is calculated dividing the absolute frequency by the total data, in this case, we approximated to the hundredth.

Length of life    Absolute Frequency      Relative Frequency     % Relative Freq.

0.2                              3                                        0.1                                10

0.3                              2                                        0.07                              7

0.4                              1                                         0.03                              3

0.5                              1                                         0.03                              3

0.7                              1                                         0.03                              3

1.0                               1                                         0.03                              3

1.2                               1                                         0.03                              3

1.3                               1                                         0.03                              3

1.5                               2                                        0.07                              7

1.8                               1                                         0.03                              3

2.0                              1                                         0.03                              3

2.3                              1                                         0.03                              3

2.5                              1                                         0.03                              3

3.0                              1                                         0.03                              3

3.3                              1                                         0.03                              3

4.0                              1                                         0.03                              3

4.5                              1                                         0.03                              3

4.7                              1                                         0.03                              3

5.0                              1                                         0.03                              3

5.5                              1                                         0.03                              3

5.6                              1                                         0.03                              3

5.9                              1                                         0.03                              3

6.0                              3                                        0.10                               10

6.5                              1                                         0.03                              3

Total                          30                                          

(c)

To calculate the sample mean we need to sum all number, which results: 83.9. Then, we divide this result to the total 30, which result: 2.80.

The sample range is the difference between the highest and the lowest value: 6.5 - 0.2 = 6.3.

The sample standard deviation is calculated trough the following process:

Step 1: Subtract the mean from each number.

Step 2: Square each result.

Step 3: Add the squared deviations.

Step 4: Divide the sum by one less the total.

Step 5: Take the square root, and there you have it.

Doing this steps, the result is 2.22.

This last process is attached:

4 0
1 year ago
Two commuters leave the same city at the same time but travel in opposite directions. One car is traveling at an average speed o
r-ruslan [8.4K]

Answer:

5 hours

Step-by-step explanation:

The formula to relate speed, distance and time is:

D = V * t

Where D is the distance, V is the speed and t is the time.

As they are in opposite directions, we need to sum the speed.

So the total speed is:

V = 63 + 59 = 122 mph

So using this value and V and using D = 610, we have:

610 = 122 * t

t = 610 / 122 = 5 hours

So they will be 610 miles apart after 5 hours.

3 0
2 years ago
Which value of y would make O P is parallel to L N?<br><br> 16<br> 24<br> 32<br> 36
natita [175]

Answer:

Step-by-step explanation:

Triangle proportionality theorem,

\frac{MO}{OL}=\frac{MP}{PN}\\\\\frac{28}{14}=\frac{y}{18}\\\\\frac{28}{14}*18=y\\\\y=\frac{28}{7}*9\\\\y=4*9\\\\y=36

8 0
1 year ago
Read 2 more answers
Other questions:
  •  A hiker is walking down a mountain. She walked​ 5,978 feet in 17 minutes. In that​ time, she descended​ 1,024 feet from the top
    7·1 answer
  • The coach of a local basketball team says that her team scored 32 points in the first game and 64 points in the second game. Wha
    8·2 answers
  • For a week Raymond is paid at the rate of x dollars per hour for the first 40 hours he works and y dollars per hour for the hour
    11·1 answer
  • Sam and Liam raced each other up and then down the hill. Sam's average speed up the hill was 1 mph, and his average speed down t
    14·1 answer
  • A closed box with a square bottom is three times high as it is wide. a) Express the surface area of the box in terms of its widt
    9·1 answer
  • Jane is taking two courses. The probablity she passes the first course is 0,7. The probablity she passes the second course is 0.
    13·1 answer
  • Fido weighs 26 pounds more than Fifi. Fifi weighs 12 pounds less than Rover. If the sum of their weights is 71, how much does Fi
    14·1 answer
  • What is the value of 3 minus (negative 2)? A number line going from negative 5 to positive 5. –5 –1 1 5What is the product? (6)
    13·1 answer
  • A researcher found a study relating the value of a car, y, to the age of the car, x. When researchers looked at the association
    7·1 answer
  • What is the value of 0²?​
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!