Please help me with the second part of this problem as I am really stuck. I have the equations listed after the problem, but don't think they are correct.

Please help me solve this at the latest by tomorrow morning. Thanks

I) Anticipating significant growth i n the air travel industry, you placed orders

totaling $2100 million to purchase new aircraft that would seat a total of

4500 passengers. Some of the aircraft were Boeing 747s that cost $200

million each and seat 400 passengers and Boeing 777s that cost $160 million

each and seat 300 passengers. Others are European Airbus A321s that cost

$60 million and seat 200 passengers. At the time you were instructed to

buy twice as many US manufactured aircraft as foreign aircraft.

a) Given the selection of three aircraft, how many of each type of aircraft did

you order?

II) Due to recent economic conditions you have been told to alter the order

for new equipment you made several years ago. The new aircraft had

not been received and placed into service yet because of the long lead

time to manufacture such complex and sophisticated equipment. The

revised budget for new aircraft is now $1810 million for 800 fewer total

passenger seats. At this point in production Boeing charges $40 million

for each 747 aircraft canceled and $35 million for each 777 aircraft

canceled. In a similar fashion Airbus charges $20 million for each A321

aircraft canceled.

b) Given that all other criteria remain the same, how many of each type of

aircraft did you cancel?

For part B I got the following equations:

1) -40x-35y-20z=290

2) 400x+300y+200z=3700

3) x+y-2z=0

I am getting the following for:

x= 113

y= -132

z=-9.5

but these numbers don't make any sense. I think I have done something wrong. Please help.