Детская задача

[ymarkov]

A farmer has a vat of 3%-fat milk and a vat of 27%-fat cream. How much of each should he use to mix 30 gallons of 4%-fat milk? Is there more than one way to solve this? (Mine looks clunky to me.)

У фермера есть молоко 3% жирности и сливки 27% жирности. Сколько того и другого ему надо смешать, чтобы получить 30 литров 4% молока? Интересно, сколько есть способов решения? (Мой кажется мне неуклюжим.)

Comments

[onionsoupmix.livejournal.com]

Okay, was this a real problem your kids got for homework? What grade?

[24816.livejournal.com]

Are you considering moving back?
-FI

[onionsoupmix.livejournal.com]

If it was elementary grades, maybe.

[24816.livejournal.com]

Elementary school kids can only invent the solution based on their intuition. The method can be TAUGHT as part of Algebra course. I don’t remember if we studied Algebra is 7th grade back in Russia. But 8th grade of 10-year-Russian-school might be close to 10th grade of 13-year-US-school.

Here are a couple of more considerations:
http://www.israelnationalnews.com/News/Flash.aspx/138831
http://www.che-be.com/news/2008-08/691/
-FI

[ymarkov.livejournal.com]

Bais Yaakov's 10th grade algebra.

[onionsoupmix.livejournal.com]

Ok, Not bad. I was hoping it was elementary school:)

[bahaltener.livejournal.com]

Elementary school probably can solve system of linear equations.

[bringing-peace.livejournal.com]

can't.
9th - 10th grade algebra

[bahaltener.livejournal.com]

May be :) It was a while ago.

[bringing-peace.livejournal.com]

In the US Algebra begins in 9th grade, so 9 for regular track, 10 - for slower track.

[bahaltener.livejournal.com]

In my time in 10th grade we were learning mathematical analysis (limits and other stuff).

[ymarkov.livejournal.com]

Да? А в моё дальше производных не заходили. Интегралы и лимиты я уже в институте учил.

[bringing-peace.livejournal.com]

in school. 10th grade.