A set of seven numbers has a mean of 25. If three numbers (20, 30, and x) are added to the set, the new mean of the ten numbers becomes 28. What is the value of x?

A 40

B 45

C 50

D 55

✓ Correct Answer: Option D

The initial sum of the 7 numbers is 7 * 25 = 175. The new total sum of the 10 numbers is 10 * 28 = 280. The three added numbers sum to 20 + 30 + x = 50 + x. So, 175 + (50 + x) = 280. This simplifies to 225 + x = 280, so x = 55.

💡 Why is D) the correct answer?

The correct answer to the question "A set of seven numbers has a mean of 25. If three numbers (20, 30, and x) are added to the set, the new mean of the ten numbers becomes 28. What is the value of x?" is Option D: 55.

The other options — A) 40, B) 45, C) 50 — are incorrect for this GRE Exam Prep question. As explained above: The initial sum of the 7 numbers is 7 * 25 = 175. The new total sum of the 10 numbers is 10 * 28 = 280. The three added numbers sum to 20 + 30 + x = 50 + x. So, 175 + (50 + x) = 280. This simplifies …

📚 About This GRE Exam Prep Practice Question

This 3-level GRE Exam Prep question from the Quantitative Reasoning topic is part of BrainForge Quiz's free exam preparation library. Each question includes the correct answer and a detailed explanation to help you understand the underlying concept, not just memorize the answer.

How to use this page: Read the question above, consider all four options (A through D), then check the highlighted correct answer and explanation. For active timed practice, start a free GRE Exam Prep practice test or use flashcards for spaced repetition review.

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A set of seven numbers has a mean of 25. If three numbers (20, 30, and x) are added to the set, the new mean of the ten numbers becomes 28. What is the value of x?

✓ Correct Answer: Option D

📚 About This GRE Exam Prep Practice Question

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