Answer:
$300
Step-by-step explanation:
The economic cost is the sum of implicit cost and explicit cost.The implicit cost is the cost by implication, which is the cost of alternative forgone.
The explicit cost is the actual cost requiring actual cash flow in settling it.
Economic cost=cost of new kindle+cost of alternative forgone(new pair of boots)
Economic cost=$150+$150
The explicit cost is also the cost incurred from accounting point of view