A survey of the opinions of 12 leading Economists in a certain country showed that, because oil prices were expected to drop in that country over the next 12 months,

10 had lowered their estimate of the consumer inflation rate,

10 had raised their estimate of the gross national product (GNP) growth rate.

3 had lowered their estimate of the consumer inflation rate but had not raised their estimate of the GNP growth rate.

How many Economists had raised their estimate of GNP growth rate and lowered their estimate of the consumer inflation rate for that period?


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To find the answer to this question, we need to analyze the given information. Let's break down the details:

- 10 economists lowered their estimate of the consumer inflation rate.
- 10 economists raised their estimate of the gross national product (GNP) growth rate.
- 3 economists lowered their estimate of the consumer inflation rate but did not raise their estimate of the GNP growth rate.

Now, let's determine the number of economists who both raised their estimate of the GNP growth rate and lowered their estimate of the consumer inflation rate.

To do this, we'll use the principle of inclusion-exclusion. According to the principle, the total number of economists who satisfies both conditions is the sum of economists who raised their estimate of the GNP growth rate and those who lowered their estimate of the consumer inflation rate, minus the number of economists who did both.

Let's calculate:

Total economists who lowered their estimate of the consumer inflation rate: 10
Total economists who raised their estimate of the GNP growth rate: 10

Total economists who both raised their estimate of the GNP growth rate and lowered their estimate of the consumer inflation rate can be calculated as follows:

Total economists who raised their estimate of the GNP growth rate + Total economists who lowered their estimate of the consumer inflation rate - Total economists who did both

10 + 10 - 3 = 17

Therefore, the answer is 17 economists who raised their estimate of the GNP growth rate and lowered their estimate of the consumer inflation rate.