Fishers Ideal Formula for calculating index numbers satisfies both Units Test and Factor Reversal Test. Let's understand both of these tests in detail:

Units Test:
The Units Test is also known as the test of consistency. The primary objective of this test is to ensure that the index number formula produces consistent results when the units of measurements of the variables change. In other words, if the units of measurement of the variables used in the index number formula are changed, the index number should not change. The Fisher's Ideal Formula satisfies this test as it is based on the concept of the geometric mean, which is a dimensionless quantity and does not depend on the units of measurement.

Factor Reversal Test:
The Factor Reversal Test is also known as the test of reversibility. The primary objective of this test is to ensure that if the original data of the variables are multiplied by a certain factor, the index number should also be multiplied by the same factor. In other words, the index number should be reversible. The Fisher's Ideal Formula also satisfies this test as it is based on the ratio of two geometric means, which is a homogeneous formula and satisfies the factor reversal property.

Therefore, we can conclude that Fisher's Ideal Formula for calculating index numbers satisfies both the Units Test and the Factor Reversal Test, making it a reliable and robust formula for calculating index numbers.

B) factor reversal test