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Posted in Mathematics

Search results for "A shipment of 18 cars, some weighing 3,000 pounds, and the others weighing 5,000 pounds each. Together the shipment has a total weight of 30 tons. (60,000 lbs). Find the number of each kind of car."


The best way to solve a problem like this is to set up two equations. First assign a variable to each thing you are trying to find. In this case, it's two different kinds of cars. Let's call the cars that weigh 3,000 pounds x, and the ones that weigh 5,000 y. The two equations you should write are:

 x+y=18 (because the problem tells you there were 18 cars in total)
3000x+5000y=60000 (because that is the total weight in the problem)

Next, you need to solve for one of the variables. I will solve for x first by subtracting y from both sides of the first equation.

x=18-y

Then you have to plug that into the other equation to get:

3000(18-y)+5000y=60000

Simplify and solve for y:

54000-3000y+5000y=60000
54000+2000y=60000
2000y=6000
y=3

Now that you know what y equals, you can put it into the equation we solved for x:

x=18-3
x=15

So there are 15 cars that weigh 3000 pounds and 3 that weigh 5000.

Related Questions

Posted in Mathematics

Find the multiplicative inverse of 6 + 2i.

The solution to the problem is as follows:

First thing to do is get rid of the i. Multiplying by 6 - 2i will do this 

( 6 + 2i)(6 - 2i) = 6^2 - (2i)^2 = 36 - 4(-1) = 36 + 4 = 40 

Dividing by 40 gets you 1 

(6 + 2i) (6-2i)/40 = 1 

The answer is (6 - 2i)/40 = (3 - i)/20

I hope my answer has come to your help. God bless and have a nice day ahead!

Posted in Mathematics

Which is a factor of 18?

Factors of 18: 1 2 3 6 9 18

hope this helps you

Posted in Mathematics

The soccer team voted on what they wanted to eat. there are 20 members on the team. six members voted for pizza, 10 voted for chicken, and the rest voted for hot dogs. which ratio represents the number of votes for hot dogs to chicken

Since there are 20 members in the soccer team. Then six members voted to eat pizza and 10 member voted to eat chicken and the rest is hotdog

Member voted for hotdog = 20 – 10 – 6 = 4

Ratio for hotdog to chicken is 10 : 4 or 5:2

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Posted in Mathematics

The price of a cup of coffee was $2.65 yesterday. today, the price fell to $2.50 . find the percentage decrease. round your answer to the nearest tenth of a percent.

We must find the difference between prices. $2.65 - $2.50 = $0.15. Now we need to calculate what percent $0.15 is of $2.65. It is 5.7%! The price decreased, so it is a 5.7% decrease!

Posted in Mathematics

The measured weights of 1,000 men in a certain village follow a normal distribution with a mean of 150 pounds and a standard deviation of 15 pounds. Which sentence most closely summarizes the data? About 160 people weigh more than 165 pounds. About 320 people weigh more than 165 pounds. About 320 people weigh less than 165 pounds. About 640 people weigh less than 165 pounds.

Z = (X-Mean)/SD 
z1 = (165 - 150)/15 = +1 
z2 = (135 - 150)/15 = - 1 
According to the Empirical Rule 68-95-99.7 
Mean +/- 1SD covers 68% of the values 
100% - 68% = 32% 
The remaining 32% is equally distributed below z = - 1 and z = +1 
32%/2 = 16% 

Therefore, 

a) Number of men weighing more than 165 pounds = 16% of 1000 = 160 
b) Number of men weighing less than 135 pounds = 16% of 1000 = 160

Posted in Mathematics

A laptop computer sells for $850. the sales tax is 7%. what is the total cost of the laptop?

Answer:

$909.50

Step-by-step explanation:

$850 x 7% = $59.50 (tax amount)

850 x (1+ 0.07) = $909.50

Posted in Mathematics

10 is %20 of what number

50 Because if you multiply 10 5 times it equals 100 percent. 

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Posted in Mathematics

If the purchase price for a house is $445,500, what is the monthly payment if you put 5% down for a 30 year loan with a fixed rate of 6.25%?

Answer:

The monthly payment is $2603.17

Step-by-step explanation:

The purchase price is = $445500

5% is down payment = 0.05\times445500=22275

Loan amount is = 445500-22275=423225

The EMI formula is = \frac{p*r*(1+r)^{n} }{(1+r)^{n}-1 }

p = 423225

r = 6.25/12/100=0.0052

n = 30*12 = 360

Putting the values in the formula we get:

\frac{423225*0.0052*(1.0052)^{360} }{(1.0052)^{360}-1 }

= $2603.17

The monthly payment is $2603.17 approx

Posted in Mathematics

List 5 numbers with 6 in the tens place

Tens place is the second digit of a number from the right. So the first number from the right is the ones place, next is the tens place, then the hundreds place and so on. The example of 6 in the tens place are:

63

161

1,265

11,269

443,462

Posted in Mathematics

A car travel 90 Km in 2 1/2 hours. How much time is required to cover 30 Km and find the distance cover in 2 hours

90:2 1/2
90/3 : (2 1/2)/3
30 : (2 1/2)/3
30 : (5/2)/(3/1)
30 : 5/2*1/3
30 : 5/6
30km in 50 mins

90 : 2 1/2
90/(2 1/2) : (2 1/2) / (2 1/2)
90/(2 1/2) : 1
(90/1)/(5/2) : 1
(90/1)*(2/5) : 1
180/5 :1
36:1
Multiply each side by 2:
72:2
72 km in 2 hours

Hope this helps :)

Posted in Mathematics

525.4 is 74% of what number

Let, that number = x
It would be: x * 0.74 = 525.4
x = 525.4 / 0.74
x = 710

So, the number would be 710

Hope this helps!

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Posted in Mathematics

The public library has fewer than 4,000 books. Let b represent the number of books in the library. Which inequality describes the number of books? b < 4,000 b > 4,000 b ≤ 4,000 b ≥ 4,000

Answer:  The correct option is (A) b < 4000.

Step-by-step explanation:  Given that the public library has fewer than 4,000 books.

We are to select the inequality that describes the number of books in the library.

The number of books in the library is represented by b.

According to the given information, the inequality hat describes the number of books in the library is given by

b<4000.

Thus, (A) is the correct option.

Posted in Mathematics

Sophia is saving money for a new bicycle. The bicycle will cost at least $623. Sophia makes $8.22 per hour. Which inequality could be used find the number of hours Sophia needs to work to make enough money to buy a new bicycle? $8.22h > $623 $8.22h ≤ $623 $8.22h ≥ $623 $8.22h < $623

Answer:

C.8.22 h\geq$ 623

Step-by-step explanation:

We are given that Sophia is saving money for a new bicycle.

The bicycle will  cost atleast $623.

Sophia makes $8.22 per hour.

We have to find the inequality that could be used to find the number of hours Sophia needs to work to make enough money to buy a new bicycle.

Let Sophia works h hours to make enough money to buy a new bicycle.

Sophia makes money per hour =$8.22

Total money made by Sophia in h hours =8.22 h

According to question

8.22 h\geq $623

Hence, option C is true.

Posted in Mathematics

Solve for x. round to nearest tenth if needed. 1. 7r-7=2r+18 a.r=-5 b.r=5 c.r=2.2 d.r=1.2 2. 2x+12=18-x a.x=3 b.x=10 c.x=6 d.x=2 3. 8x-3=15x+18 a.x=-3 b.x=3 c.x=2.1 d.x=0.9 4. 6y-6=4y+16 a.y=2.2 b.y=-2.2 c.y=11 d.y=5 5. 3(x-4)=5(x+2) a.x=11 b.x=-11 c.x=1 d.x=-1

1)  The answer is: [B]: r = 5 .
__________________________
Explanation:
__________________________ 
Given: 7r − 7 = 2r + 18 ; Round your answer to the nearest tenth, if necessary.
____________________________
Since "r" is the only variable given, let us assume we want to solve for "r" (instead of "x").
___________________________
→ Subtract "2r" from EACH SIDE of the equation; and & add "7" to EACH SIDE of the equation:
_____________
→ 7r − 7 − 2r + 7 = 2r + 18 − 2r + 7 ;  to get: → 5r = 25 ;
_____________
→ Now, divide EACH SIDE of the equation by "5"; to isolate "r" on one side of the equation; and to solve for "r" :
______________
→ 5r / 5 = 25 / 5 → r = 5 → which is: "Answer choice: [B]".
_________________
Let us check our answer, by plugging in "5" for "r" in the original equation:
_________________
 → 7r − 7 = 2r + 18 ;  →  7(5) − 7 =? 2(5) + 18? ;
______________________
→ 35 − 7 =? 10 + 18 ?;     → 28 =? 28? Yes!
______________________
 2) The answer is: [D]: x = 2 .
_____________
Explanation: 
_____________
Given: 2x + 12 = 18 − x ; Solve for "x" (round to nearest tenth, if necessary).
_______________
→ Add "x" to EACH SIDE of the equation, & subtract "12" from EACH SIDE of the equation:  → 2x + 12 + x − 12 = 18 − x + x − 12 ; 
______________
→ To get: 3x = 6 ;  → Divide EACH SIDE of the equation by "3";
to isolate "x" on one side of the equation; and to solve for "x":
_____________
→ 3x / 3 = 6 / 3 ; → x = 2 ; which is: "Answer choice: [D]".
______________
Let us check our answer, by plugging in "2" for "x" in the original equation:
________________
→ 2x + 12 = 18 − x ; → 2(2) + 12 =? 18 − 2 ?
________________
→ 4 + 12 =? 18 − 2 ? ;   → 16 =? 16?  Yes!
________________________________
3)  The answer is: [A]: x = -3 . 
_____________
Explanation:
________________
Given:  8x − 3 = 15x + 18 ; Solve for "x". Round your answer to the nearest tenth, if necessary.
_________________
→ Subtract "8x" from EACH SIDE of the equation, & add "3" to EACH SIDE of the equation:
_______________
→ 8x − 3 − 8x + 3 = 15x + 18 − 8x + 3 ; to get:
_______________
→ 0 = 7x + 21 ; → Subtract "21" from EACH SIDE of the equation;
_______________
→ 0 − 21 = 7x + 21 − 21 ; to get:
_______________
→  -21 = 7x ; Now divide EACH SIDE of the equation by "7";
    to isolate "x" on one side of the equation; & to solve for "x":
_______________
→ = -21 / 7 = 7x / 7 ; →  -3 = x ; which is "Answer choice: [A]."
_________________
Let us check our answer, by plugging in "-3" for "x" in the original equation:
________________
→  8x − 3 = 15x + 18 ;  → 8(-3) − 3 =?  15(-3) + 18 ?;
________________________
→ -24 − 3 =?  -45 + 18 ? ;   →  -27 =? -27?  Yes!
___________________________
4)  The answer is: [C]: y = 11 .
_____________
Explanation:
____________
Given: 6y − 6 = 4y + 16 ; Solve for "y"; Round to the nearest tenth, if necessary.
____________
(Note: Since "y" is the only variable given; assume we are to solve for "y" instead of "x").
____________
→ Subtract "4y" from EACH SIDE of the equation, & add "6" to EACH SIDE of the equation; → 6y − 6 − 4y + 6 = 4y + 16 − 4y + 6 ; to get:
_______________
→ 2y  = 22 ; Now, divide EACH SIDE of the equation by "2"; to isolate "y" one side of the equation; and to solve for "y" ;
_______________
→ 2y / 2 = 22 / 2 ; →  y = 11 → which is "Answer choice: [C]".
_______________________________
Let us check our answer, by plugging in "11" for "y" in the original equation:
___________________
→  6y − 6 = 4y + 16 ; → 6(11) − 6 =? 4(11) + 16 ?
_______________________
→ 66 − 6  =? 44 + 16 ?  → 60 =? 60 ?  Yes!
__________________
5)  The answer is: [B]: x = -11 .
_____________________
Explanation:
_________________
Given: 3(x − 4) = 5(x + 2) ; Solve for "x". Round to the nearest tenth, if necessary.
___________
→Note the "distributive property of multiplication": 
_____________
a*(b + c) = ab + ac ;  and: a*(b − c) = ab − ac ;
_______________
→ Let us expand EACH SIDE of our given equation.
→Start with the "left-hand side":
____________
3(x − 4) = (3*x)  − (3*4) = 3x − 12;
______________________________
→Now let us expand the "right-hand side" of the given equation:
____________
→  5(x + 2) = (5*x) + (5*2) = 5x + 10 ;
______________
→Now, we can rewrite the original equation:
_______________
→ 3(x − 4) = 5(x + 2) ; by substituting the expanded values for EACH SIDE of the question:   →  3x − 12 = 5x + 10 ;
__________________
→ Subtract "3x" from EACH SIDE of the equation; and add "12" to EACH SIDE of the equation: →  3x − 12 − 3x + 12 = 5x + 10 − 3x + 12 ; to get:
________________
→  0 = 2x + 22;  → Now subtract "22" from EACH SIDE of the equation:
______________
→  0 − 22 = 2x + 22 − 22 ; to get:  →  -22 = 2x ;
__________
→ Divide EACH SIDE of the equation by "2"; to isolate "x" on one side of the equation; & to solve for "x" ;
_____________
→  -22 / 2 = 2x /2 ;  →  -11 = x ; which is "Answer choice: [B]".
______________
Let us check our answer, by plugging in "-11" for "x" in the original equation:
___________
→ 3(x − 4) = 5(x + 2) ; →  3(-11 − 4) =? 5(-11 + 2) ? ; 
_______________________
→3(-15) =? 5(-9) ? ; → -45 =? -45 ?  Yes!
_____________________________________________
Hope these answers and explanations are helpful. Best of luck!

Posted in Mathematics

Mrs. Donley's math class has a total of 25 students. On Friday, the class was given an eight question quiz on fractions. The number of incorrect answers given by the students is shown below. Incorrect Answers Number of Students 0 5 1 7 2 4 3 6 4 2 5 1 What is the relative frequency of students that missed 1 question on the quiz? A. 0.28 B. 0.48 C. 0.35

You need to find the amount of students who missed one question, and divide that by the total number. If you sum all the students, you find that there are 25 students. From the chart, 7 missed 1 question, therefore the solution would be 7/25, which is 0.28, or A.

A. 0.28

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Posted in Mathematics

Is 30y^2 a polynomial?

No. polynomials are expressions that have two or more terms in them. 30y² is a single term, or a monomial. the prefix poly- means many and the prefix mono- means one, for future reference.

Posted in Mathematics

How to estimate 184÷9 in multiplication

Do you mean checking your work? In that case it would be 9*20.

Posted in Mathematics

Your $1000 investment in an energy stock doubles. Your $1000 investment in a tech stock drops in half. What was the total return on the two investments?

Total return, when measuring performance, is the actual rate of return of aninvestment or a pool of investments over a given evaluation period. Total returnincludes interest, capital gains, dividends and distributions realized over a given period of time.

So the total return = (1000*2) + (1000/2) = $2500

Posted in Mathematics

Find the value of 3x + 2 when 7+ x = 5

I hope this helps you




x= 5-7


x= -2


3.(-2)+2


-6+2


-4

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Posted in Mathematics

Find all the zeros of the function y=x^3+6x^2+x+6

Y=X^3+6x^2+X+6 that is your answer
one more thing X= not real solution

Posted in Mathematics

How can you solve 0.01×30

You can just do 1x30 which equals 30

Posted in Mathematics

WILL UPVOTE! Which equation is related to 89 = x + 61? A. x = 150 B. 61 = 89 + x C. x = 28 D. x = 18

C! x = 28. If you use simplification, and then you find the answer and use it in the equation, it would be correct.

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