AoPSWiki
Want to learn how to tackle those tough MATHCOUNTS and AMC counting and probability problems? Check out Art of Problem Solving's Introduction to Counting & Probability by David Patrick.

2006 Cyprus MO/Lyceum/Problem 1

From AoPSWiki

Problem

A diary industry, in a quantity of milk with 4\% fat adds a quantity of milk with 1\% fat and produces 1200kg of milk with 2\% fat. The quantity of milk with 1\% fat, that was added is (in kg)

\mathrm{(A)}\ 1000\qquad\mathrm{(B)}\ 600\qquad\mathrm{(C)}\ 800\qquad\mathrm{(D)}\ 120\qquad\mathrm{(E)}\ 480

Solution

Let x be the number of kg of 4\% milk and let y be the number of kg of 1\% milk.

We then have the equations x+y=1200 and \frac{4x+y}{100}=1200*.02=24.

Solving, we find X=400, and y=1200-400=800\Rightarrow\mathrm{(C)}.

See also

2006 Cyprus MO, Lyceum (Problems)
Preceded by
First Question
Followed by
Problem 2
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Want to learn how to tackle those tough MATHCOUNTS and AMC counting and probability problems? Check out Art of Problem Solving's Introduction to Counting & Probability by David Patrick.
© Copyright 2008 AoPS Incorporated. All Rights Reserved. • FoundationPrivacyContact Us