Linear equation from a verbal sentence: If 24 is subtracted from a number, the result is four-sevenths of the original number. What is the sum of the digits of that number?

Difficulty: Easy

Correct Answer: 11

Explanation:


Introduction / Context:
Translate the statement into an equation, solve for the number, then compute the sum of its digits. This is a straightforward linear equation in one variable with a follow-up digit-sum calculation.

Given Data / Assumptions:

  • x − 24 = (4/7) x.
  • x is an integer (implied by a sensible “digits” question).


Concept / Approach:
Collect x terms on one side. Solve for x by isolating it using standard algebra. Then add the digits of the resulting number.


Step-by-Step Solution:

x − (4/7)x = 24.(3/7)x = 24 ⇒ x = 24 * 7 / 3 = 56.Sum of digits of 56 = 5 + 6 = 11.


Verification / Alternative check:
Check the sentence: 56 − 24 = 32 and (4/7)*56 = 32. Equality holds; digit sum 11 is confirmed.


Why Other Options Are Wrong:

  • 1, 9: Not the digit sum of 56.
  • Data inadequate: The equation uniquely determines x.


Common Pitfalls:
Subtracting in the wrong direction or mishandling fractions when moving terms. Multiply both sides as needed to avoid fraction errors.


Final Answer:

11

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