Final answer:
Money resolves the inefficiency in trading known as the 'double coincidence of wants' that is found in a barter system, by providing a common medium of exchange that facilitates trade and specialization.
Step-by-step explanation:
The student is asking about the role that money plays in eliminating the need for a certain economic condition. Money is a medium of exchange that allows individuals to trade efficiently. In the context of an economy, it means that money eliminates the need for people to have a double coincidence of wants. This is a situation where two parties each desire what the other has to offer, which was necessary in a barter system. With money, people can specialize in their labor and use the income they earn to purchase what they need, without having to find a perfect barter match.