kaplan unclear answer

hi guys , actually I’m preparing to take f9 paper in this December , and i have come across this question in kaplan textbook Q4 made to order product ,and here in the question :

A company has produced a made-to-order product for a customer at a cost of $50,000, which was to have been sold to the customer for $120,000.
The customer has now gone bankrupt.
The company has the option of converting the product into a different version which it estimates could be sold for $85,000.
The conversion would require the following:
(1) 1,000kgs of material A. The company currently has 2,500kgs in stock which was bought last month for $2.00 per kg, although the current purchase price has now increased to $2.15. Material A is regularly used in the company’s other products.
(2) 2,000kgs of Material B. The company currently has 600kgs in stock which was bought last month for $3.00 per kg although the current purchase price is now $3.50. There is no other use for the material and it has a scrap value of $1.00 per kg.
(3) 4,000 hours of skilled labour. Skilled labour is paid a fixed weekly wage and there is currently spare capacity sufficient to provide half the required hours. The remaining hours
(4) Each set of gears requires 0.5 kg of titanium at $600/kg, 10 hours of skilled labour, 4 hours of unskilled labour and 2 hours in the automated finishing room.
(5) Skilled workers are paid $10 per hour with time and a half for overtime. They are guaranteed 2,000 hours per annum; however, at present the 15 workers are only 90% utilised. No further skilled workers will be recruited. Unskilled workers are paid $7 per hour and are only hired when needed.
(6) The finishing room incurs variable costs of $10 per hour when in use. At present the production of Wotton Inc’s existing machine components fully utilises the room, generating contribution of $5 per hour. For the first two years Sue will have to cut back on this production in order to have sufficient capacity to finish the new product. However, in two years’ time the finishing room will be expanded at a cost of $2,000 in order that production of the old product can be brought back up to its current levels.
(7) The cycle parts venture would also require the use of an existing machine (net book value = $40,000) which would otherwise be sold for $60,000. The asset is expected to be worthless in five years’ time. would be made up through overtime which would be paid at $12 per hour.
Requirement
Perform calculations to show whether the company should convert the product.

and the answer to it was like following :

Sales value if converted 85,000

Material A
(1,000kgs @ $2.15) – replacement cost (2,150)

Material B
Amount in stock (600kg @ $1) – scrap proceeds lost (600)

Amount not in stock (1,400kg @ $3.50) – purchase cost (4,900)

Skilled labour
Spare capacity 0

Extra hours required (2,000hrs @ $12) (24,000)

Semi skilled labour
(3,000hrs@ $10) – revenue lost – material cost saved (30,000)

Machine – replacement cost (15,000)
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Relevant value of the conversion 8,350
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every steps in answering the question was sensible to me except the part related to the replacement cost of the machine , i couldn’t figure out from were did they got that number 15000 USD

so could any one please help me in sorting this issue

appreciate