Tutors Answer Your Questions about Proportions (FREE)
Question 571263: you have a total of 60 cupcakes; 36 are choc. You want 70% choc. How many more cupcakes do you need to bake ?
Answer by scott8148(5882)   (Show Source):
Question 569745: What is the last digit (ones) of the product of the positive prime
numbers less than 50?
Show and explain how you got your answer.
Answer by Alan3354(21587)  (Show Source):
You can put this solution on YOUR website!What is the last digit (ones) of the product of the positive prime
numbers less than 50?
Show and explain how you got your answer.
------------
It's zero.
One of the numbers is 2 and another is 5 --> xxxxxxx0
Question 569360: four-sevenths of a school's faculty are women. four-fifths of the male faculty members are married, and nine of the male faculty are unmarried. how many faculty members are there?
Answer by IWork4Dessert(57)  (Show Source):
You can put this solution on YOUR website!Let's work this from the end to the start. You know two things about the male faculty members, so begin with those. 4/5 of the men are married, and 9 of them are not. This means that 1/5 of the men are unmarried, so 9 is 1/5 of the total amount of men. Now you can set up a proportion:
1/5=9/x
Solve the proportion by cross-multiplying.
x=45
There are 45 men total. You know now that since 4/7 of the faculty are women, then 3/7 of them are men. So you have another proportion:
3/7=45/x
Cross-multiply again.
3x=315
Divide both sides by 3 to get the variable(letter) alone.
x=105
105 people are in the faculty total.
Question 569349: i need help with 3/2=18/8
Answer by solver91311(12126)  (Show Source):
Question 569347: whats 2/5 = 4/n what does n equal
Answer by IWork4Dessert(57) (Show Source):
You can put this solution on YOUR website!In a proportion, you're basically doing the opposite of simplifying a problem, you're expanding it. When you see one, think to yourself: "Two over five is the same as four over what?"
2/5=4/n
1. Cross-multiply.
2n=20
2. Divide both sides by the number next to the variable(the letter) to get the variable alone.
n=10
There's your answer!
You know this is right because if you multiply 2/5 by 2, it equals 4/10.
Question 567594: P is inversely proportional to d^2
P = 10,000 when d = 0.4
Find the value of P when d = 0.8
I know that P = k/ d^2
so .. k/ 0.64 = 10,000
but i dont know how to use the numbers given to find the value
Answer by Earlsdon(6103) (Show Source):
Question 567525: 66 is 40% of what number?
Answer by stanbon(48545) (Show Source):
Question 566744: What is the Ratio in simplest form 28 inches to 40 inches
Answer by jim_thompson5910(21667) (Show Source):
Question 566552: What is 'x' in 20-x/x=6/4
Answer by Maths68(1154)  (Show Source):
Question 566306: 54 over 72 = x over 100
Answer by Tias_411(14)  (Show Source):
Question 565997: Suppose that y is directly proportional to x.
If y=12 when x=-4, what is the value of y when x=25?
Answer by Horlaye(3)  (Show Source):
You can put this solution on YOUR website!solution: y=xk (where k is the constant)
subtitute the values for x and y
12=4k
divide both side by the co-efficient of k
12/4=4k/4
k=3
the law connecting the two variables : y=3x
when x = 25
y = 3x
y = 3(25)
y = 75
the value of y =75
Question 566005: Nine identical pipes can fill a tank in 4hours. Given that the rate of water flow in all the pipes are the same, find how long it would take six of these pipes to fill the same tank.
Answer by josmiceli(6784)  (Show Source):
You can put this solution on YOUR website!If 9 pipes fill the tank in 4 hrs, then
1 pipe would take 9 times as long,
or  hrs to fill the tank.
---------------------------
It would take 6 pipes 1/6 of that time
to fill the tank, or  hrs
Question 565640: 16 winners out of 200 entries and 28 winners out of 350 entries
Answer by stanbon(48545) (Show Source):
Question 565526: What percent of 72 is 18? Use proportions.
Found 2 solutions by ad_alta, stanbon:
Answer by ad_alta(170)  (Show Source):
Answer by stanbon(48545) (Show Source):
You can put this solution on YOUR website!What percent of 72 is 18? Use proportions.
------------------
x/100 = 18/72
x = 1800/72 = 25
--------------------
Ans: 25%
====================
Cheers,
Stan H.
=============
Question 565017: You were assigned a locker for your books at school. You forgot the locker number but remember that two of the 12 positive factors of the locker number are 6 and 25. What is your locker number? Show or explain how you got your answer.
Answer by issacodegard(60)  (Show Source):
You can put this solution on YOUR website!We know that 6=2*3 and 25=5*5. Since 6 and 25 are divisors of the locker number call it x, and since 6 and 25 have no common prime factors, 2*3*5*5 must be a divisor of x. Therefore, 1, 2, 3, 5, 5*5, 2*3, 2*5, 2*5*5, 3*5, 3*5*5, 2*3*5, 2*3*5*5 are distinct divisors of x. But there are 12 divisors listed, so they must be the only 12 divisors of x. So the 2*3*5*5=150 must be the locker number.
Question 563815: A bottle is half full. AFter adding 275mL to the bottle it is three quarters full. How much does the bottle hold when full?
Answer by stanbon(48545) (Show Source):
You can put this solution on YOUR website!A bottle is half full. AFter adding 275mL to the bottle it is three quarters full. How much does the bottle hold when full?
----
Let the bottle's capacity be "x":
Equation:
(1/2)x + 275 = (3/4)x
-----
(2/4)x + 275 = (3/4)x
(1/4)x = 275
---
x = 1100 mL
=================
Cheers,
Stan H.
=================
Question 563628: 8 men build a fence in 6 days. How much time will it take 12 men to build the same fence?
Answer by Alan3354(21587) (Show Source):
You can put this solution on YOUR website!8 men build a fence in 6 days. How much time will it take 12 men to build the same fence?
--------
The job takes 48 man-days (8 men * 6 days)
48 man-days/12 men = 4 days
Question 563500: a scale model of the eiffel tower is 5 inches tall. if the real eiffel tower is 450 ft. tall, what is the scale of the model?
Answer by kindle(1) (Show Source):
Question 213023: by weight, the ratio of chlorine to sodium in table salt is 35.46 to 23.00. How much sodium is contained in 50.00kg or salt? Has to be set up as an appropriate proportion and then be solved.
Answer by math108(1) (Show Source):
You can put this solution on YOUR website!Who did you take Math 108 with?
by weight, the ratio of chlorine to sodium in table salt is 35.46 to 23.00. How much sodium is contained in 50.00kg or salt? Has to be set up as an appropriate proportion and then be solved.
:
Let x = amt of sodium in 50 kg
then
(50-x) = amt of chlorine in 50 kg
;
A ratio equation:
=
cross multiply
35.46x = 23(50-x)
35.46x = 1150 - 23x
35.46x + 23x = 1150
58.46x = 1150
x =
x = 19.67 kg of sodium
;
:
check:
Chlorine: 50 - 19.67 = 30.33
:
23/35.46 = .6486
19.67/30.33 = .6485; close enough
Question 562937: My teacher gave the answer -12. What is the steps to solve?
x/8 - 8 = -12
Answer by mananth(10549)  (Show Source):
Question 562772: The ratio of copper to tin is 23 to 2, if a bronze trophy has a mass of 2250g what is the mass of tin in the trophy?
Answer by ankor@dixie-net.com(12692)  (Show Source):
You can put this solution on YOUR website!The ratio of copper to tin is 23 to 2,
if a bronze trophy has a mass of 2250g what is the mass of tin in the trophy?
:
 * 2250 = 180 gr of tin
Question 562585: 48 is 70% of what number?
Answer by solver91311(12126) (Show Source):
Question 561517: 15 is what percent of 10
24 is what percent of 50
what percent of 20 is 8
If you can help me with this plz help me thank u and plz show the work.
Answer by rfer(10417) (Show Source):
Question 560853: What is 60% of 120?
Answer by rfer(10417) (Show Source):
Question 560548: On a map, 1 inch equals 13.3 miles. Of two cities are 4.5 inches apart on the map, how far are they acutally apart
Answer by jim_thompson5910(21667) (Show Source):
Question 560295: what does it mean to equate the cross product?
hat size head circumference head circumference
7 7/8 24 61
7 1/2
Answer by KMST(592)  (Show Source):
You can put this solution on YOUR website!THE PROBLEM
The hat size, head circumference in inches, and head circumference in centimeters are in direct proportion.
They tell you that a hat size of 7 7/8 will fit a head circumference of 24 inches or 61 centimeters.
You want to know the head circumference in inches (x), and in centimeters (y) corresponding to a hat size of 7 1/2.
WHAT IS MEANT BY CROSS PRODUCTS
To find the head circumference in inches (x) corresponding to a hat size of 7 1/2 you would write the proportion
 = 
To get to an equivalent equation without denominators, you would multiply both sides of the equal sign by the denominators
By doing that, and simplifying, you would get a simpler equation with one product equated (stated as equal) to another product:
The equated products involve numbers that were placed crisscross from each other in the original equation. That's why they are called "cross products".
When you are solving the problem, you can just say that the cross products are equal, and save yourself any further explanations and intermediate steps.
THE SOLUTION
For the circumference in centimeters (x), we write
=
Equating cross products we get
We write the mixed numbers as improper fractions to get
 ---> 
Multiplying both sides by  we get
 ---> 
which could be expressed as the mixed number 
or it could be approximated as the decimal 
However, since it's a circumference measurement in inches, a more appropriate answer would be 23 inches.
For the circumference in centimeters (x), we write
 = 
Equating cross products we get
 or 
So  or  which simplifies to
 , and calculates to approximately 58 centimeters.
Question 560236: Find the unknown quantity for the following ratios and proportions.
The scale on a blueprint indicates that ½ " equals 10 feet. What would be the ratio for this blueprint?
(NOTE: Format answer as # in:# ft) (Use no periods after abbreviations.)
Answer by rapaljer(4551)  (Show Source):
Question 560232: Please show the ratio answer as #:#.
Of the 13 Journeymen on a jobsite, there are 5 females. What is the ratio of males to females on this job?
Answer by rapaljer(4551) (Show Source):
You can put this solution on YOUR website!The total numberr of Journeypeople is 13, of which 5 are female. This means that the other 13-5=8 are males.
The ratio of male to female is 8:5.
Dr. Rapalje, Retired
Question 559930: 3x*16=12*4
Answer by bucky(2097) (Show Source):
You can put this solution on YOUR website!You are asked to solve for x given the equation:
.
3x*16=12*4
.
Before we begin, let's remember that 3x means 3 times x. So x is being multiplied by 3. With that in mind we can think of 3x as being written as 3*x to show the multiplication. So really the left side of the equation can be written as shown below:
.
3*x*16 = 12*4
.
Think about this: In a series of multiplications we can arrange the terms in any order as long as we end up multiplying all the terms. For example, if you were given a multiplication problem such as 4*6*5*2 you could multiply it in the order given or in other orders such as 5*4*2*6 or maybe 2*4*5*6 or 5*6*2*4. It doesn't make any difference in what order you do this multiplication you will always get 240 as an answer.
.
Now let's get back to your problem. The left side of the equation is 3*x*16. We can rearrange the terms to 16*3*x and then multiply the 16 times 3 first. 16 times 3 is 48. Then we multiply the 48 times x and get 48x. So with this form the equation has become:
.
48x = 12*4
.
Now on the right side multiply the 12*4 to get 48 and this makes the equation:
.
48x = 48
.
Finally, divide both sides of this equation by the number multiplying the x. That number is 48. When you divide 48x by 48 the answer is just x. So the left side of the equation is now just x. But don't forget ... since you divided the left side by 48 you must also divide the right side by 48. 48 divided by 48 is just 1. So we have reduced the equation to be:
.
x = 1
.
and that's the answer.
.
We can check this answer by returning to the original problem and replacing x by 1 to see if the left side of the equation equals the right side. If it does, then our answer for x is correct.
.
The original problem was:
.
3x*16=12*4
.
We replace x by 1 and the original problem becomes:
.
3*1*16 = 12*4
.
When you multiply 3 times 1 times 16 you get 48. And on the right side of the equation when you multiply 12 times 4 you get 48. So with x = 1, the equation simplifies to:
.
48 = 48
.
Our answer checks. If x were something other than 1, the left side would not have equaled the right side so we would know that this was a wrong value for x.
.
I hope this explanation helps you to understand a little more about algebraic equations.
.
Question 559429: There is an interview where 100 people were interviewed and asked questions about if they heard a specific song on the radio television or both. 50 people listened to it on the radio, 30 people heard it on the television, and 20 people heard it on both. My question is: How and why does P(heard it on the television or radio) the same as P(heard it on the radio + heard it on the television - heard it on both)?
Answer by Theo(2973)  (Show Source):
You can put this solution on YOUR website!the answer depends on how the categories have been created.
if you separate people who have heard it on both radio and tv in a separate category, then what you get is the following:
radio only = 50
tv only = 30
both = 20
total people = 100
probability of someone hearing it on the radio = (50 + 20)/100 * 100% = 70%
probability of someone hearing it on the tv = (30 + 20)/100 * 100% = 50%
probability of someone hearing it on both = 20/100 * 100% = 20%
notice that the probability of someone hearing it on the radio includes the number of people who heard it on both, and the probability of someone hearing it on the tv also includes the number of people who heard it on both.
now, when you are given the probability of someone hearing it on radio and you are given the probability of someone hearing it on tv, and you want to find the number of people who heard it on the tv or on the radio, you would need to subtract the number of people who heard it on both to remove the double counting.
you would get:
number of people who heard it on radio or on tv = 70% + 50% - 20% = 100%
the subtraction of the probability of the number of people who heard it on both is necessary to remove the double counting.
Question 558781: 2/v = 1/8
Answer by rapaljer(4551) (Show Source):
You can put this solution on YOUR website! means 
Therefore,  means 
I have an easy to understand explanation on Ratio and Proportion on my website. To go to my website, use the easy-to-spell and easy-to-remember link www.mathinlivingcolor.com. At the very bottom of this page, there is a link that will take you to my Homepage.
Once you are on my Homepage, look for the link "Basic, Intermediate, and College Algebra: One Step at a Time." Choose "Basic Algebra", and look in "Chapter 3," Section 3.08 Ratio and Proportion" for a complete, non-traditional explanation that my own students, before I retired, found a lot easier to understand than the published textbooks of that day. You should really like my MATH IN LIVING COLOR pages, where the most difficult problems are solved IN COLOR. In addition, I have a video of me teaching this topic before I retired.
Everything on the website is FREE. If you find something you really like, just print your own copy of it!!
If anyone needs to contact me, especially about the website, my Email address is rapaljer@seminolestate.edu. I'll be glad to help you find an explanation on my website to help you with your algebra topic!
Dr. Robert J. Rapalje, Retired
Seminole State College of Florida
Altamonte Springs Campus
Question 558226: 5:200 as X:40
X=
Answer by rapaljer(4551) (Show Source):
You can put this solution on YOUR website! means that
 means that 
For additional help with this, please see my own FREE website. To go to my website, use the easy-to-spell and easy-to-remember link www.mathinlivingcolor.com. At the very bottom of this page, there is a link that will take you to my Homepage.
I have a section about Ratio and Proportion on my website. Once you are on my Homepage, look for the link "Basic, Intermediate, and College Algebra: One Step at a Time." Choose "Basic Algebra", and look in Chapter 3, Section 3.08 for a complete, non-traditional explanation that my own students, before I retired, found a lot easier to understand than the published textbooks of that day. You should really like my MATH IN LIVING COLOR pages, where the most difficult problems are solved IN COLOR.
Everything on the website is FREE. If you find something you really like, just print your own copy of it!!
If anyone needs to contact me, especially about the website, my Email address is rapaljer@seminolestate.edu. I'll be glad to help you find an explanation on my website to help you with your algebra topic!
Dr. Robert J. Rapalje, Retired
Seminole State College of Florida
Altamonte Springs Campus
Question 558139: a school purchased five new basketballs for 149.95. at that rate, how much more money will it cost the school to have 12 new basketballs in all?
Answer by rfer(10417) (Show Source):
Question 558128: what is 15 to 4 as 9 to 2 times a number
Answer by rfer(10417) (Show Source):
Question 558152: if y=45 when x=9, find y when x=7 solve.
Answer by edjones(7311)  (Show Source):
Question 558040: X:30 as 4:10
X=
Answer by saifoo.khan(153)  (Show Source):
Question 557954: 5:200 as X:40
X=
Answer by Alan3354(21587) (Show Source):
You can put this solution on YOUR website!Do it like this one.
----
20:60 as X:50
------
Multiply the means and extremes, or the inners and outers.
20*50 = 60x
x = 1000/60 = 50/3
Question 557953: X:30 as 4:10
X=
Answer by Alan3354(21587) (Show Source):
You can put this solution on YOUR website!Do it like this one.
----
20:60 as X:50
------
Multiply the means and extremes, or the inners and outers.
20*50 = 60x
x = 1000/60 = 50/3
Question 557951: 20:60 as X:50
x=
Answer by Alan3354(21587) (Show Source):
Question 557694: 0.05:X as 0.15:30
X=
Answer by stanbon(48545) (Show Source):
Question 557668: 1/2:2 as 1/4:X
X=
Answer by jim_thompson5910(21667) (Show Source):
Question 556107: 3/y=12/17 need help on how do i solve this
Answer by ankor@dixie-net.com(12692) (Show Source):
Question 555865: how d i sovle this problem 7/3=52/n n=
Answer by jim_thompson5910(21667) (Show Source):
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