May I have a little arithmetic help?

[Rosedala]

Hello, my face is SO red but...could you help me get the best price on the following please? (It's olive oil):

(A) 3 litters (3 quarts & 5 oz) $28.00
(B) 1 liter (33.8 oz) $11.00
(C) 25.5 oz (750 ml) $ 8.00
(D) 1 pint (9.35 oz) (750 ml) $ 7.50
(E) 16.9 oz. (500 ml) $ 6.00

(Strange that both: 25.5 oz and 9.35 oz., should be 750 ml?)

Thanks ever so much!

Rosedala

 

[Deleted member 4993]

Hello, my face is SO red but...could you help me get the best price on the following please? (It's olive oil):

(A) 3 litters (3 quarts & 5 oz) $28.00 ? = 28/101 $/oz =0.277227723 $/oz
(B) 1 liter (33.8 oz) $11.00 ? = 11/33.8 $/oz =0.325443787 $/oz
(C) 25.5 oz (750 ml) $ 8.00? = 8/25.5 $/oz =0.31372549 $/oz
(D) 1 pint (9.35 oz) (750 ml) $ 7.50 ? = 7.5/16 $/oz =0.46875 $/oz
(E) 16.9 oz. (500 ml) $ 6.00 ? = 6/16.9 $/oz =0.355029586 $/oz

(Strange that both: 25.5 oz and 9.35 oz., should be 750 ml?) ? NO

Thanks ever so much!

Rosedala

1 US fluid ounce = 29.5735296 ml ? 25.5 fl. oz = 754.1250048 ml and 1 pint = 16 oz = 473.1764736 ml



1 ml = 0.0338140227 US fluid ounces

 

[mmm4444bot]

Strange that both: 25.5 oz and 9.35 oz., should be 750 ml?

I'm thinking that 9.35 oz is bad information.

One pint is 16 oz, not 9.35 oz.

Hi Rosedala:

To compare prices, we need prices that are all based on the same measuring unit for the amount of olive oil.

To find the best buy, you want to compare "unit prices". A unit price is the cost for one unit of volume; there are many different possible unit prices for each of these olive-oil items because there are many different units of volume (eg: price per ounce, price per liter, price per milliliter, price per quart, price per pint). We need to pick only one.

Start by converting the volume of each item to the same unit. (I'll pick milliliters, for this post).

Next, divide each item's price by its volume in milliliters.

EG:

1-pint item = 473 ml (rounded)

This item's price is $7.50 .

7.5 ÷ 473 = 0.0159

We see that one milliliter of olive oil in this pint costs us 1.59 cents, so this particular unit price for the pint container is "$0.0159 per ml".

Realize that prices are not changing; we're just restating them with a common unit. In other words, "$7.50 per pint" is equal to "$0.0159 per ml".

Finish by comparing the milliliter unit-prices for the five items; the best buy is the item for which one milliliter of olive oil costs the least amount of money.

At stores, unit prices sometimes* appear on items' shelf price-tags (usually near the lower righthand corner). This makes it easy to compare value between items.

In the image below, a unit price is shown as "0.399 PER 100G". The unit price on a different sized bag of flour might display as "0.295 PER 100G". The latter bag is the better value because you're saving just over a dime on every 100G of flour.

[attachment=0:3rfwmopr]unitprice.jpg[/attachment:3rfwmopr]

Cheers,

~ Mark



* When stores don't care about consumers easily comparing prices, they allow either changes in units between similar items (i.e., the price tag for one brand of honey shows $0.50 per oz and for another brand of the same honey $0.0279 per ml) or displaying the unit price as "EXEMPT" (in regulated areas) or simply blank. Bastards.

 

[Rosedala]

(A) 3 litters (3 quarts & 5 oz) $28.00 ? = 28/101 $/oz =0.277227723 $/oz
(B) 1 liter (33.8 oz) $11.00 ? = 11/33.8 $/oz =0.325443787 $/oz
(C) 25.5 oz (750 ml) $ 8.00? = 8/25.5 $/oz =0.31372549 $/oz
(D) 1 pint (9.35 oz) (750 ml) $ 7.50 ? = 7.5/16 $/oz =0.46875 $/oz
(E) 16.9 oz. (500 ml) $ 6.00 ? = 6/16.9 $/oz =0.355029586 $/oz

I like your signature, Subhotosh, very clever...I'll have to keep it in mind! I thank you so very much for all the great information you've provided me, I'm going to digest it slowly and hopefully I'll be able to understand numbers and calculate them myself in the future.

The prices in red mean cents per each ounce? i.e.: (A) 28¢, (B) 33¢, (C) 31¢, (D) 47¢, and (E) 36¢? There's no question the big can (A) is the winner, though more difficult to handle. Would it make sense to get instead the easier-to-handle bottle (C) at 31¢ which is only 3¢ more per ounce?

Again my gratitude for your very valuable help!

Rosedala

 

[Rosedala]

Hello and thanks so much, Mark, for the wonderful information you sent me! Together with Subhotosh's help, I can now do some homework at my own pace and try calculating prices myself the next time.

I'm thinking that 9.35 oz is bad information.
One pint is 16 oz, not 9.35 oz.

You're right I must've misread the label. I'll go back to the store to check it again. But by now I believe I shall buy plenty of bottles at 31¢ per ounce, (C) in my little list, since I've seen they are still going up almost each time I go to the store.

Again, you are right I should've taken the weights in only one unit, either ounces or milliliters, except that, as you well described it, the manufacturers deliberately I'm sure, indicate weights in different units and different quantities to make it difficult to calculate. The 5 items I checked, all had different units and quantities - enough to drive anyone crazy let alone someone like me who can't understand numbers... lol! Certain items, as you well say, do show the unit prices (per ounce or per count, etc.) but not all. There ought to be a law about this, and if there is one, there should be more enforcing of it...

Per your paragraph below, is it then almost 2¢ per milliliter?

We see that one milliliter of olive oil in this pint costs us 1.59 cents, so this particular unit price for the pint container is "$0.0159 per ml".

Armed with your thorough information and that of Subhotosh, I'll be able to resolve my arithmetic compounded problem of never being sure where to put (or to read) the dots and the zeros on the left, especially when converting one type of unit to another...

I'm saving the 2 sets of information in a special email folder so I can get to it quickly and easily to study it and practice on it.

I'm most grateful for your very valuable help! Rosedala

 

[Deleted member 4993]

But by now I believe I shall buy plenty of bottles at 31¢ per ounce, (C) in my little list, since I've seen they

Why ???

(C) is more expensive than (A) (= 28 ¢/oz) - unless there is quality difference - or shelling out $28 in one shot becomes painfull!!!

 

[mmm4444bot]

… the manufacturers deliberately I'm sure, indicate weights in different units and different quantities to make it difficult to calculate …

I agree that it's sometimes deliberate, but I'm thinking that merchants are responsible, not manufacturers.

… There ought to be a law about this, and if there is one, there should be more enforcing of it...

Some areas are regulated, but there's too many loopholes, and most consumers don't have an opinion.

… is it then almost 2¢ per milliliter?

With the pint container, rounded to the nearest cent, yes. I'd say "almost one and a half cents per ml", instead.

Watcha cookin' ?

 

[Rosedala]

(A) 3 litters (3 quarts & 5 oz) $28.00 ? = 28/101 $/oz =0.277227723 $/oz
(C) 25.5 oz (750 ml) $ 8.00? = 8/25.5 $/oz =0.31372549 $/oz

(C) is more expensive than (A) (= 28 ¢/oz) - unless there is quality difference - or shelling out $28 in one shot becomes painfull!!!

Hi Subhotosh! I thought that while (A) at 28 cents is the best price per oz, since it's a can and difficult to handle, with only 3 cents difference per oz wouldn't (C) at 31 cents be the next best price? The quality seems approximately the same.

Yes, it's always painful to have to disburse so much for a necessity item, but, that's life. I use olive oil a lot exclusively (no dressings sauces, etc.) hence searching for best buy and then get a quantity.

Again, so gratefully yours! Adela

 

[Rosedala]

Hi Mark, and thanks for confirming my question about the cents per milliliter! Just checking on myself to see if I can understand, at least partly, all those numbers despite John von Neumann's theory about not understanding them but getting used to them lol! I hope to get both ways.

Again I thank you a lot for the lessons! Adela

 

[Denis]

I use olive oil a lot exclusively (no dressings sauces, etc.)......

Ya? Thought olive oil was a medecine: pour in your ears to soften the wax!

 

[Deleted member 4993]

(A) 3 litters (3 quarts & 5 oz) $28.00 ? = 28/101 $/oz =0.277227723 $/oz
(C) 25.5 oz (750 ml) $ 8.00? = 8/25.5 $/oz =0.31372549 $/oz

(C) is more expensive than (A) (= 28 ¢/oz) - unless there is quality difference - or shelling out $28 in one shot becomes painfull!!!

Hi Subhotosh! I thought that while (A) at 28 cents is the best price per oz, since it's a can and difficult to handle, with only 3 cents difference per oz wouldn't (C) at 31 cents be the next best price? The quality seems approximately the same.


(A) is approximately $1 cheaper at (C) volume. That is, if you could get 25.5 oz (volume of C) at (A) price - you would pay $7 instead of $8. Ofcourse, (bottle vs. can), (tying up money), (storage availability) etc. come into individual shopping decision.


Yes, it's always painful to have to disburse so much for a necessity item, but, that's life. I use olive oil a lot exclusively (no dressings sauces, etc.) hence searching for best buy and then get a quantity.

We, in our family, do the same - buy from Sam's club.



Again, so gratefully yours! Adela

 

[mmm4444bot]

People make fun of me, sometimes, when I buy stuff in bulk (eg: 144 rolls of TP in the corner of a spare bedroom).

Yet, I've never seen them laugh when I pick up their tabs at the watering hole.

 

[Deleted member 4993]

Re:

People make fun of me, sometimes, when I buy stuff in bulk (eg: 144 rolls of TP in the corner of a spare bedroom).

Yet, I've never seen them laugh when I pick up their tabs at the watering hole.

Real fun would be to make them pick up your tab!!!!