急求一道经济题!

题目

急求一道经济题!
1.SweatersInc.sells sweaters in the US and in Canada.The production of sweaters is describedbelow.All firms are in the US unlessnoted.
Yarns Inc.buys wool from the Haslett Sheep Farm for $ 1,000
Yarns Inc.spins the wool into yarn.
Knitters Co buys yarn from Yarns Inc.for $ 1,500
Knitters Co knits 400 sweaters
Sweaters inc buys 400 sweaters from Knitters Co for $ 6,000
Sweaters inc buy 400 boxes from The Box co.of Costa Rica $ 1,200
Sweaters Inc.markets and sells the 400 sweaters
US buyers buy 300 sweaters for $40 each $12,000
Canadian buyers buy 100 sweaters for $40 each $ 4,000
How muchdoes the production of sweaters sold by Sweaters Inc.add to the U.S.GDP?

答案