Question

Horses cost $10, pigs cost $3, and rabbits are only $0.50. a farmer buys 100 animals for $100. how many of each animal did he buy? there are two correct answers.

Answer 1

You can use the following equation:

10h+3p+0.5r=100

This equation uses “h” “p” and “r” to represent the number of animals bought, each variable having a coefficient which is that animal's price. The right side is the total price.

You will now need a second equation so you can proceed to substitution/elimination:

h+p+r=100

This equation, using the same variables, represents the total number of animals to be bought.

We can eliminate the “h” variable by multiplying the bottom equation by -10, you now have the following:

10h+3p+0.5r=100

-10h-10p-10r=-1000

Add down and the result is:

-7p-9.5r=-900

You can set up a proportion

-9.5r=-900+7p

r=(-900+7p)/-9.5

And substitute in the original equation…

P.S. I challenge you to figure out the rest on your own because it is really just a tedious process of substitution and elimination from here and my phone is about to die. I'll check in later if you're still having problems.