Final answer:
Expression C (9100 x 2/5) is not a correct way to calculate 25% of 9100 because 2/5 represents 40%, not 25%, which is the required percent to calculate.
Step-by-step explanation:
The question asks which of the provided expressions is not a way to calculate 25% of 9100. To find 25% of a number, you can multiply the number by 0.25, divide the number by 4, or multiply the number by the fraction 25/100 since all these operations will yield the same result (which is the definition of 25 percent).
- Expression A (9100 x 0.25) is correct because 0.25 represents 25% as a decimal.
- Expression B (9100/4) is correct because dividing by 4 is the same as calculating 25% (one quarter).
- Expression C (9100 x 2/5) is not correct because 2/5 represents 40%, which is different from 25%.
- Expression D (9100 x 25/100) is correct because 25/100 simplifies to 25%, which is exactly what we want to calculate.
Therefore, Expression C is the one that does not correctly calculate 25 percent of 9100.