10 llamas and 20 ostriches cost $14,000. 20 llamas and 10 ostriches cost $13,000. What does 1 llama cost?

Question

Please help me with this

Answer 1

let the cost of 1 llama be x and that of 1 ostrich be y

 

so first equation becomes   10x +20 y= 14000  ie  x+2y=1400 ( after dividing both sides by 10)

second eq becomes              20 x +10 y= 13000 ie  2x+y= 1300 (same reason)

 

multilpyinh the second eq by 2    we get                 4x + 2y= 2600

 

 

subtract the first equation from this new equation we got

 

we get       3x= 2600-1400= 1200 

 

 

so x is 400 which is the cost of one llama:)