What is the double coincidence of wants, and why does it hinder barter?

• A. It occurs when both traders want exactly the same good, making trades straightforward.
• B. It occurs when each trader must want the other's offer at the same time, making exchanges rare and costly.
• C. It refers to the need for a single currency to exist for trade.
• D. It happens when money is absent and trades are only possible with barter.

Answer: (B)

The double coincidence of wants means that for a trade to happen in barter, each party must want exactly what the other is offering at the same moment. This creates inefficiency because finding a match requires two people to desire the specific goods the other has, and to value them appropriately at the same time. If the farmer wants shoes but the shoemaker doesn’t want grain right now, or timing doesn’t line up, no trade occurs. This makes exchanges rare and costly due to search, timing, and valuation mismatches. Money solves this by serving as a widely accepted medium of exchange, eliminating the need for a simultaneous desire for a specific good.