Margie is responsible for buying a week's supply of food and medication for the dogs and cats at a local shelter. The food and medication for each...

Hello!

Denote the cost of supplies for a dog as d and for a cat as c (in dollars).

Then the first condition may be written in terms of d and c as

d=2*c.

The second condition is

24*d+155*c=1152.

Start from the substitution method, substitute d from the first equation into the second:

24*2*c+155*c=1152, or c=1152/203 approx 5.67($).

And therefore d=2*1152/203 approx 11.34($).

Now for the elimination method. Multiply the first equation by -24 and add it to the second equation. This will eliminate d:

155c=1152-2*24c, or (155+48)*c=1152,

c=1152/203. And d=2*c=2*1152/203.

The result is the same, which isn't a surprise.

The answer: for each dog 11.34$ may be spent approximately.