Answer:
Imports = Bottle of wines
Imports = 40 * $30 = $1,200
Exports = Spark plugs
Exports = 200 * $5 = $1,000
Net Exports = Exports - Imports
Net Exports = $1,000 - $1,200
Net Exports = -$200
Consumption = Surfboard + Wines
Consumption = $670 + $1,200
Consumption = $1,870
Government purchase = $0
Investment = $0
GDP = C + I + G + NX
GDP = $1,870 + $0 + $0 + (-$200)
GDP = $1,870 + $0 + $0 - $200
GDP = $1,670