the infirmary

[SILVER]

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]

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]

Thanks a ton