Ok, this is really sad, but I am stumped and cannot figure out even a 5th grade math problem!!!

So I am going to post this and ask that you guys find the answer and PLEASE tell me how you got it so I don't look like a moron when I try to tell my kids how to do this thing!!

Here is the question....

At lunch, 50 children bought either chocolate or white milk. Chocolate milk costs $0.30 and white milk costs $0.25. The total cost of the milk sold was $13.30. How many chocolate milks and white milks were sold?

 

The answer I'd give is, "Who the heck cares as long as I got MY milk!"

Questions like that are the reason I was in a remedial math class my senior year in high school.

Sorry I couldn't help.

chaikwa.

 

c+w=50
0.3c+0.25w=13.30

c=50-w

0.3(50-w)+0.25w=13.30

15-0.3w+0.25w=13.30

-0.05w=-1.7

w=34
c=16

 

I always thought formulas were too hard so i used estimate and close in procedure.

40*.25 = $10.0
10 *30 = $3

Thats 50 milks at $13. We need to come up with 30 cents more but keep the same. Chocolates cost $.05 more, so we need 6 more cholates than whites in our current number.

34 * .25 = $8.50
16 * .30 = $4.80

= $13.30

 

x = number of white milk
y = number of chocolate milks
x + y = 50 (50 milks sold)
.25x + .30y = 13.30 (total dollar value of milk sold)
solve both equations for for y
y= 50 - x and y = (13.30 - .25x)/.30
y = y
50-x = (13.30-.25x)/.30 (multiply both sides by .30)
15 - .3x = 13.30 - .25x (subtract 15 from both sides and add .25x to both sideds)
-.05x = -1.7 (divide -1.7 by -0.5)
x=34 (number of white milks)
y = 50 - x (equation 1)
y = 16 (number of chocymo)

 

btw, dont feel bad, I have tutored college students that couldn't have done that one.

 

OR;
Scratchin' your head yet Jack? I know mine's swimmin'!

chaikwa.

 

uhhhhhhhhh, are we sure this isn't 25th grade math?

 

Nope... I have a 6th grader and a 7th grader. I have been thru this a few times in the past couple years.

granted its not something most people use.
most people would have kept up with their milk sales as they were happening or have known how many they started with and finished with.

 

and aside from math class, where is any 5th grader going to need this "knowledge" in real life?

 

I think knowing how to estimate and figure out is good but most people don't know how to do this equation, unless I'm really dumb. lol

 

anyways... thanks for the help, guys. That was awesome.

 

DTR???????

 

I don't think any of the posted solutions came from 5th graders (unless I'm drastically mistaken).

 

my answer came from a slow typing engineer.