Difference between revisions of "2006 Cyprus MO/Lyceum/Problem 1"

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==Solution==
 
==Solution==
{{solution}}
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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
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<math>x+y=1200</math>
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<math>4x+y=2400</math>
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<math>3x=1200</math>
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<math>x=400</math>
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<math>y=1200-400=800 \Rightarrow \mathrm {(C)}</math>
  
 
==See also==
 
==See also==
 
{{CYMO box|year=2006|l=Lyceum|before=First Question|num-a=2}}
 
{{CYMO box|year=2006|l=Lyceum|before=First Question|num-a=2}}

Revision as of 19:14, 19 October 2007

Problem

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

A. $1000$

B. $600$

C. $800$

D. $120$

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

$x+y=1200$

$4x+y=2400$

$3x=1200$

$x=400$

$y=1200-400=800 \Rightarrow \mathrm {(C)}$

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