Fractions: 3/5 of the vehicles in a parking lot is cars, 7/20 is pickups.

[10mostwanted]

Hello,

Would like some help with the following:

1.3/5 of the vehicles in a parking lot is cars, 7/20 is pickups. The remaining 4 is SUV's.

a) What fraction of the vehicles is SUV's?
b) How many vehicles are in the parking lot?
c) How many cars are in the park?

Your assistance with working is appreciated.

Thanks a million!

 

[ksdhart2]

Well, considering you've posted this exercise in the "Arithmetic" sub-forum, I'm not sure how familiar you are with variables, but I think you'll need to use them to solve this exercise. We know that the total number of vehicles in the parking lot will be the number of cars, plus the number of pickups, plus the number of SUVs. We also know that, in word problems, the word "of" means to use multiplicationhttp://www.purplemath.com/modules/translat.htm. If you let the variable V stand for the total (currently unknown) number of vehicles in the parking lot, then can you create an expression for the number of cars, being "3/5 of the total?" Can you create an expression for the number of pickups, being "7/20 of the total?" Based on those, and noting that the problem tells us there are exactly four SUVs, what equation can you create to help you solve the problem? (Hint: It will be of the form V = [something]. Recall what what we earlier determined about the number of vehicles in the lot)

Give the problem a shot and see how far you can get. If you get stuck again, that's okay, but when you reply back, please include any and all work you've done on the problem, even the parts you know for sure are wrong. Thank you.

 

[mmm4444bot]

The three fractions (two of which are given) need to add up to 1.

Add 3/5 and 7/20.

Subtract that total from 1.

The result will be the fraction of the whole lot that is SUVs.

 

[sean]

1.3/5 of the vehicles in a parking lot is cars, 7/20 is pickups. The remaining 4 is SUV's.

a) What fraction of the vehicles is SUV's?
b) How many vehicles are in the parking lot?
c) How many cars are in the park?

a) Ok so the first thing you always need to do with fractions is get everyone on the same level. It's like having a good team everyone needs to be able to understand each other.

I don't know your level of fractions so I'll start from the beginning. In a case like this all your fractions should add up to 1. And it's important to remember that 1 represents 100%. So the the 1.3/5 represents a certain percentage and so does 7/20. So you know that 1.3/5 added to 7/20 added to the fraction of SUV's is 1 (i.e. 1.3/5 + 7/20 + (fraction of SUV's = 1).

Right so wee need everyone to relax and get on the same level. Which means get a 'common denominator' (again absolutely no idea your level of maths so google it and find a 5min video explaining it if you don't understand that and come back, because that is a key element to fractions).

So we have:

1.3 + 7 + x = 1 (where x is equal to the fraction of SUVs. You could represent it as a if it makes it easier to visualize)
5 20 b
___________ = 1 (In this case 20 is your common denominator because it's the smallest number 5 & 20 will divide into)
20
-------------------------------------------------------------------------------------------------------------------------------------------------
1.3 + 7 + x = 1
5 20 (next you divide 5 into 20 and you get 4 and multiply it by 1.3)
1.3(4)_____ = 1 (*again if you don't understand common denominators you're going to be confused try Khan academy videos)
20
-------------------------------------------------------------------------------------------------------------------------------------------------
1.3 + 7 + x = 1
5 20 (next you divide 20 into 20 and you get 1 and multiply it by 7)
1.3(4)+7(1) + x = 1
20
-------------------------------------------------------------------------------------------------------------------------------------------------
So isolating our new common denominator equation we get:

1.3(4) + 7(1) + x = 1
20 20

cleaning up we get:

5.2 + 7 + x = 1
20 20

Adding the fractions we get:

12.2 + x = 1
20

Subtracting both sides by the fraction:

12.2 + x - 12.2 = 1 - 12.2 ====> x = 1 - 12.2 ====> x = 7.8 OR SUV fraction = 7.8 20 20 20 20 20 20

Ok so 7.8/20 is the SUV's fraction

b) Next we need to find the number of vehicles in the parking lot.

Well we know there are 4 SUVs and that their fraction is 7.8/20 so this is just simple algebra.

We know 4 = 7.8/20 and we're looking for 20/20 as the number of vehicles.

if we divide both sides of of the equation by 7.8 we get:

4/7.8 = 1/20 (and again we're looking for 20/20)

So we multiply both sides by 20

4(20)/7.8 = 20/20 =====> 10.256 = 20/20

So according to this there are 10.256 vehicles so I hope either someone else can confirm or find out where I went wrong. I have after doing it a different way and it came out the same so I don't know maybe your teacher hates you because having .256 of a vehicle seems a bit mean.

c) From part a) we know that 5.2/20 of the vehicles are cars.

so (10.256/20)*5.2 = 2.67 cars

 

[Deleted member 4993]

1.3/5 of the vehicles in a parking lot is cars, 7/20 is pickups. The remaining 4 is SUV's.

a) What fraction of the vehicles is SUV's?
b) How many vehicles are in the parking lot?
c) How many cars are in the park?

a) Ok so the first thing you always need to do with fractions is get everyone on the same level. It's like having a good team everyone needs to be able to understand each other.

I don't know your level of fractions so I'll start from the beginning. In a case like this all your fractions should add up to 1. And it's important to remember that 1 represents 100%. So the the 1.3/5 represents a certain percentage and so does 7/20. So you know that 1.3/5 added to 7/20 added to the fraction of SUV's is 1 (i.e. 1.3/5 + 7/20 + (fraction of SUV's = 1).

Right so wee need everyone to relax and get on the same level. Which means get a 'common denominator' (again absolutely no idea your level of maths so google it and find a 5min video explaining it if you don't understand that and come back, because that is a key element to fractions).

So we have:

1.3 + 7 + x = 1 (where x is equal to the fraction of SUVs. You could represent it as a if it makes it easier to visualize) ← The first fraction is 3/5 and NOT 1.3/5
5 20 b
___________ = 1 (In this case 20 is your common denominator because it's the smallest number 5 & 20 will divide into)
20
-------------------------------------------------------------------------------------------------------------------------------------------------
1.3 + 7 + x = 1
5 20 (next you divide 5 into 20 and you get 4 and multiply it by 1.3)
1.3(4)_____ = 1 (*again if you don't understand common denominators you're going to be confused try Khan academy videos)
20
-------------------------------------------------------------------------------------------------------------------------------------------------
1.3 + 7 + x = 1
5 20 (next you divide 20 into 20 and you get 1 and multiply it by 7)
1.3(4)+7(1) + x = 1
20
-------------------------------------------------------------------------------------------------------------------------------------------------
So isolating our new common denominator equation we get:

1.3(4) + 7(1) + x = 1
20 20

cleaning up we get:

5.2 + 7 + x = 1
20 20

Adding the fractions we get:

12.2 + x = 1
20

Subtracting both sides by the fraction:

12.2 + x - 12.2 = 1 - 12.2 ====> x = 1 - 12.2 ====> x = 7.8 OR SUV fraction = 7.8 20 20 20 20 20 20

Ok so 7.8/20 is the SUV's fraction

b) Next we need to find the number of vehicles in the parking lot.

Well we know there are 4 SUVs and that their fraction is 7.8/20 so this is just simple algebra.

We know 4 = 7.8/20 and we're looking for 20/20 as the number of vehicles.

if we divide both sides of of the equation by 7.8 we get:

4/7.8 = 1/20 (and again we're looking for 20/20)

So we multiply both sides by 20

4(20)/7.8 = 20/20 =====> 10.256 = 20/20

So according to this there are 10.256 vehicles so I hope either someone else can confirm or find out where I went wrong. I have after doing it a different way and it came out the same so I don't know maybe your teacher hates you because having .256 of a vehicle seems a bit mean.

c) From part a) we know that 5.2/20 of the vehicles are cars.

so (10.256/20)*5.2 = 2.67 cars

.

 

[mmm4444bot]

I hope either someone else can confirm or find out where I went wrong.

The original post has a typo:

"1.3/5 of the vehicles..."

There should be a space between the exercise number (1.) and the beginning of the exercise statement (3/5 of the vehicles...)

 

[10mostwanted]

Error in question - its 3/5 not 1 3/5

The below is correct my apologies and thanks for all your assistance!

The original post has a typo:

"1.3/5 of the vehicles..."

There should be a space between the exercise number (1.) and the beginning of the exercise statement (3/5 of the vehicles...)

 

[10mostwanted]

My answer - This is Grade 4/5 work So Can't Be too Complicated

Hi all this is the working I originally had and your assistance helped it make sense. This is grade 4-5 work so don't think the amount of working is too in depth.

1). 1 or (20/20) - 3/5 + 7/20

12 + 5 = 19/20
20

20/20 - 19/20 = 1/20

1/20 vehicles = 4 cars
Ans for 1) = 1/20

2). (X = vehicles)
1/20 X = 4 cars
X = 20 x 4
total vehicles = 80
Ans for 2) = 80 vehicles in the parking lot

3). 3/5 x 80
= 48
Ans for 3) = 48 cars in park

Extra:
7/20 x 80
= 28 pickups

48 cars + 28 pickups + 4 SUVs = 80 vehicles

Couldn't figure it out without all of your help!

 

[ksdhart2]

All of your answers are good, I just have one correction. It might seem minor right now, but it will be important in the future. You say that the fraction of cars in the lot is "20/20 - 3/5 + 7/20." You calculated the correct answer, but the written part is incorrect. It should be either 20/20 - (3/5 + 7/20) or 20/20 - 3/5 - 7/20. Make sure you understand why that is.

 

[10mostwanted]

All of your answers are good, I just have one correction. It might seem minor right now, but it will be important in the future. You say that the fraction of cars in the lot is "20/20 - 3/5 + 7/20." You calculated the correct answer, but the written part is incorrect. It should be either 20/20 - (3/5 + 7/20) or 20/20 - 3/5 - 7/20. Make sure you understand why that is.

Understood (BODMAS is boss)! I had included in my revised working thanks!