The mean of x and y is 400 , and the ratio of x to y is 3 : 7 . What is the value of y - x ? - Quantitative Aptitude MCQ Competitive Exam Practice 2026 | ExamTest.live

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The mean of x and y is 400, and the ratio of x to y is 3 : 7 . What is the value of y - x ?

Solution & Step-by-step Explanation

Given: Mean of x and y = \frac{x + y}{2} = 400 ⟹ x + y = 800 The ratio is given as x : y = 3 : 7 . Let x = 3 k and y = 7 k . 3 k + 7 k = 800 10 k = 800 ⟹ k = 80 We need to find y - x : y - x = 7 k - 3 k = 4 k 4 k = 4 \times 80 = 320

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The mean of x and y is 400, and the ratio of x to y is 3 : 7 . What is the value of y - x ?

130

800

320

230

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