Final answer:
The increase in the cost of groceries is an example of inflation. Inflation refers to the general increase in prices over time, which reduces the purchasing power of money. In this case, the price of groceries has risen from $100 to $120, meaning that the same amount of money can now buy fewer groceries.
Step-by-step explanation:
The situation described in the question is an example of inflation. Inflation refers to the increase in the general level of prices over time. When prices rise, the purchasing power of money decreases.
In this case, the cost of groceries has increased from $100 to $120 per week. This means that the same amount of money can now buy fewer groceries. Although you are buying the same quantity of groceries, the increased prices have resulted in a decrease in the purchasing power of your money.
It is important to note that inflation affects not only groceries, but also other goods and services in the economy. It is a common phenomenon that occurs as a result of factors such as increased production costs, changes in demand and supply, and monetary policy.