the infirmary

SILVER

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Jan 27, 2011
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how do I solve this problem? Is it a problem with 2 unknowns? or just a normal equation?

At the infirmary, four aspirin and five bandages cost a total of $49. Four aspirin and eight bandages cost $64. How much does an aspirin cost?
 

masters

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Mar 30, 2007
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SILVER said:
how do I solve this problem? Is it a problem with 2 unknowns? or just a normal equation?

At the infirmary, four aspirin and five bandages cost a total of $49. Four aspirin and eight bandages cost $64. How much does an aspirin cost?

Hi Yo Silver,

It will be a system of 2 linear equations.

Let a = cost of aspirin

Let b = cost of bandage

[1] \(\displaystyle 4a\:+\:5b\:=\:49\)
[2] \(\displaystyle 4a\:+\:8b\:=\:64\)

Subtract the two equations:

[3] \(\displaystyle -3b\:=\:-15\)

[3] \(\displaystyle \boxed{b\:=\:\$\:5.00}\)

Substitute this answer into [1] or [2] to find a.

 

SILVER

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Jan 27, 2011
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Thanks a ton
 
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