Math Problem Statement

When 40% of a number is subtracted from 120, the answer is 26.66% of the number. Find the number.

Solution

Let's solve the given problem step-by-step.

Problem:

  • 40% of a number is subtracted from 120.
  • The result is 26.66% of the same number.
  • We need to find the original number.

Solution:

Let the unknown number be xx.

  1. 40% of the number:
    40%ofx=0.4x40\% \, \text{of} \, x = 0.4x

  2. Equation setup:
    Subtracting 0.4x0.4x from 120 gives 26.66%26.66\% of the same number: 1200.4x=0.2666x120 - 0.4x = 0.2666x (Note: 26.66%26.66\% as a decimal is 0.26660.2666).

  3. Rearrange the equation: 120=0.4x+0.2666x120 = 0.4x + 0.2666x Combine like terms: 120=0.6666x120 = 0.6666x

  4. Solve for xx: x=1200.6666180x = \frac{120}{0.6666} \approx 180


Final Answer:

The original number is approximately 180.


Do you need further details or have any questions?


Here are 5 related questions to deepen your understanding:

  1. What happens if the percentage values are changed? Can the same method be used?
  2. How do we handle cases where the result is a fraction of a different number?
  3. What is the impact of rounding decimals like 26.66%26.66\% on calculations?
  4. How would you write this equation if the unknown value were in a different position?
  5. Can you express the problem in terms of ratios instead of percentages?

Tip: When dealing with percentages in equations, always convert them to decimals to simplify calculations.

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Math Problem Analysis

Mathematical Concepts

Algebra
Percentages
Equations

Formulas

Percentage formula: x% of a = (x/100) * a
Equation solving: ax + b = c

Theorems

Basic properties of percentages and equations

Suitable Grade Level

Grades 8-10