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2 years ago

Seven less than three times a number is 5. Find the number

Mathematics

2 answers:

Anit [1.1K]2 years ago

7 0

Step-by-step explanation:

it is 12 because 12 - 7 is 5 the number 4 is the number multiplied by 3

bagirrra123 [75]2 years ago

5 0

<u>Answer</u>:

the number is 4

<u>Explanation</u>:

let the number be b :)

3b - 7 = 5 { three times a number; seven less of that number; is 5 }

3b = 5 + 7 { changed sides }

3b = 12 { divide both sides by 3 }

b = 4 { final answer }

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A music store sold a total of 27 used trumpets and clarinets in one month. Trumpets cost $149 and clarinets cost $99. If total s

vodomira [7]

Answer: 16

Solution:

1) Use letters to identify the variables:

Number of trumpets: t
Number of clarinets: c

2) Translate each statement into algebraic (mathematical) language.

2.1) Sold a total of 27 used trumpets and clarinets

=> t + c = 27

2.2) Trumpets cost $149 and clarinets cost $99

Total cost of the trumpets: 149t
Total cost of clarinets: 99c

Total cost = 149t + 99c

2.3) Total sales were $3223

=> 149t + 99c = 3223.

3) State the system of equations:

Equation (1) t + c = 27
Equation (2) 149t + 99c = 3223

4) Solve the system of equations:

4.1) Multiply equation 1 by 149:

=> 149t + 149c = 4023

4.2) Subtract the equation (2) from the equation obtained in 4.1

=> 149c - 99c = 4023 - 3223

=> 50c = 800

=> c = 800 / 50 = 16

5) Verify the solution:

From equation (1) t = 27 - 16 = 11

Total cost = 149*11 + 99*16 = 3223

Now you have a verified answer: they sold 16 clarinets

7 0

4 years ago

Write a real word problem that can be represented by the equation 3/4c=21

svetlana [45]

How many 3/4 cups of milk would be needed to make 21 cups of milk for a large recipe?

4 0

3 years ago

Megan has $15,000 to invest. She is considering two investment options. Option A pays 3.2% simple interest. Option B pays 4.1% i

True [87]

wheee

Compute each option

option A: simple interest

simple interest is easy

A=I+P

A=Final amount

I=interest

P=principal (amount initially put in)

and I=PRT

P=principal

R=rate in decimal

T=time in years

so given

P=15000

R=3.2% or 0.032 in deecimal form

T=10

A=I+P

A=PRT+P

A=(15000)(0.032)(10)+15000

A=4800+15000

A=19800

Simple interst pays $19,800 in 10 years

Option B: compound interest

for interest compounded yearly, the formula is

$A=P(1+r)^t$

where A=final amount

P=principal

r=rate in decimal form

t=time in years

given

P=15000

r=4.1% or 0.041

t=10

$A=15000(1+0.041)^{10}$

$A=15000(1.041)^{10}$

use your calculator

A=22418.0872024

so after 10 years, she will have $22,418.09 in the compounded interest account

in 10 years, the investment in the simple interest account will be worth $19,800 and the investment in the compounded interest account will be worth$22,418.09

4 0

3 years ago

Read 2 more answers

A random sample of 20 purchases showed the amounts in the table (in $). The mean is $49.57 and the standard deviation is $20.28.

son4ous [18]

Answer:

The 98% confidence interval for the mean purchases of all customers is ($37.40, $61.74).

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.98}{2} = 0.01$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.01 = 0.99$ , so $z = 2.325$

Now, find M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

$M = 2.325*\frac{20.28}{\sqrt{20}} = 12.17$

The lower end of the interval is the mean subtracted by M. So it is 49.57 - 12.17 = $37.40.

The upper end of the interval is the mean added to M. So it is 49.57 + 12.17 = $61.74.

The 98% confidence interval for the mean purchases of all customers is ($37.40, $61.74).

3 0

3 years ago

The figure below is a right rectangular prism. which expression represents the volume of the prism?

Leviafan [203]

Answer: The expression (equation/formula) for the volume of a:

" right rectangular prism " ; is represented by:

____________________________________________________

→ " V = L * w * h " ;

____________________________________________________

in which: all the dimensions are in the same "units of measurement" (or converted to the same "units of measurement" ;

and in which:

" V " is the "volume" of the right rectangular prism; in the "cubic units" ; or written as: "units³ " ; or, [insert the particular units used}^ ³ " ;

→ that is, [units] raised to the "3rd [third] power" ; assuming these units are the same same "fundamental units of measurement" as the "other 2 (two) values in the expression".

If we are given no specific units of measurement whatsoever, then we use the generic term, "units" as the "units of measurement" ; and we express the "volume; "V" ; of a "right rectangular prism" as: " units ³ " ; or "cubic units" ;

in our answer— if we are asked to solve for the:

"volume; "V"; of a "right rectangular prism" ;

_________________________________________________

and in which:

"L" represents the "length" of a "right rectangular prism" ;

"w" represents the "width" of a "right rectangular prism" ;

"h" represents the "height" of a "right rectangular prism" .

_________________________________________________

To given an example:

Say we have a "right rectangular prism" ; with the given measurements:

width , "w" : w = 2 units;

length, "L" : L = 3 units ;

height, "h" : h = 8 units.

_________________________________________________

We are asked to "find the volume " ; of this "right recentangular prism" .

The formula for the volume; "V" ; of this "right rectangular prism" ;

is:

_________________________________________________

→ Volume = Length * width * height ;

that is:

→ V = L * w * h ;

Solve for the volume; "V" .

_________________________________________________

→ V = L * w * h ; Now plug in the values given:

→ V = (3 units) * (2 units) * (8 units) ;

= 3 * 2 * 8 * (units) * (units) * (units) ;

= 3 * 2 * 8 * units ³ ;

= 48 units ³ .

_________________________________________________

Hope this answer— and explanation—is helpful to you!

Wishing you the best in your academic pursuits

— and within the "Brainly" community!

_________________________________________________

4 0

3 years ago

Read 2 more answers