general math MCQ #726

A positive number, when decreased by 4, becomes 21 times its reciprocal. What is the number?

general math MCQ #726

Question 1
Q1. A positive number, when decreased by 4, becomes 21 times its reciprocal. What is the number?
- A) 5
- B) 6
- C) 7
- D) 8
Answer: 7
Explanation: Setting up x − 4 = 21/x gives x² − 4x − 21 = 0, which factors as (x−7)(x+3) = 0; the positive solution is x = 7.