use the following information to calculator explicit cost and implicit cost.

a Moffat and Spieder put $70,000 of their own money into the form.

b they bought equipment for 40,000

c they hired one employee to help them for an unusual wage of $18,000

d Moffat gave up her previous job, at which she earned $22,000,and spent all her time working for MSCF.

e Spieder kept his old job, which paid $20 hours of leisure each week (for 50 weeks) to work for MSCF.

f MSCF bought $5,000 of goods from other form.

g the market value of the equipment at the end of the year was $37,000.

the answer is

Explicit costs are $23,000. Explicit costs are all the costs for which there is a payment. Explicit costs are the sum the wages paid ($18,000) and the goods and services bought from other firms ($5,000). [2 marks]

Implicit costs are the sum of the costs that do not involve a payment. Implicit costs are the sum of the interest forgone on the $70,000 put into the firm; the $22,000 income forgone by Moffat not working at her previous job; $20,000, which is the value of 1,000 hours of Spieder's leisure (20 hours a week for 50 weeks); and the economic depreciation of $3,000 ($40,000 minus $37,000). [3 marks]

但是我不明白为什么b不算explicit cost 呢