Answer: It is better to buy and accept the offer.
Step-by-step explanation:
Making cost :
Direct Material = cost × No. of telephones manufactures
= 4 × 4000
= 16,000
Direct Labour = cost × No. of telephones manufactures
= 16 × 4,000
= 64,000
Variable overhead = cost × No. of telephones manufactures
= 12 × 4000
= 48,000
Fixed overhead = cost × No. of telephones manufactures
= 12 × 4000
= 48,000
Total cost:
= Direct Material + Direct Labour + Variable overhead + Fixed overhead
= 16,000 + 64,000 + 48,000 + 48,000
= $176,000
Buy cost :
Purchase price = Per unit price × No. of telephones purchase
= 31 × 4000
= 124,000
Fixed overhead = Fixed overhead from making - fixed overhead eliminated
= 48,000 - 20,000
= 28,000
Total cost = Purchase price + Fixed overhead
= 124,000 + 28,000
= 152,000
Therefore, it is better to buy and accept the offer.