Correct Answer:
C. 80
This question asks us to find a number when a certain percentage of it is known. We are given that 25% of a number is 20.
- Understanding Percentages: 25% can be expressed as a fraction (1/4) or a decimal (0.25).
- Setting up the equation: Let the unknown number be 'x'. The problem states that 25% of x is 20, which can be written as 0.25 * x = 20.
- Solving for x: To find x, divide 20 by 0.25: x = 20 / 0.25. Alternatively, since 25% is 1/4, if 1/4 of the number is 20, the whole number is 4 times 20.
- Calculation: 20 / 0.25 = 80, or 20 * 4 = 80.
Thus, the number is 80. Options A (60), B (70), and D (90) are incorrect because 25% of these numbers are 15, 17.5, and 22.5 respectively, not 20.