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JEE Main 201815 AprilMorning ShiftOnline
Exam
JEE Main
Year
2018
Date
15 April
Shift
Morning Shift
Mode
Online
Subject
Mathematics
Chapter
Statistics

JEE Main 2018 · 15 April · Morning Shift · Online · Mathematics · Statistics

The mean of a set of 30 observations is 75 . If each other...

The mean of a set of 30 observations is 75 . If each other observation is multiplied by a nonzero number λ\lambda and then each of them is decreased by 25 , their mean remains the same. The λ\lambda is equal to equal to {0}\{0\}

Options

  1. A103\frac{10}{3}
  2. B43\frac{4}{3}
  3. C13\frac{1}{3}
  4. D23\frac{2}{3}

Correct answer

B. 43\frac{4}{3}

Step-by-step solution

As mean is a linear operation, so if each observation is multiplied by λ\lambda and decreased by 25 then the mean becomes 75 λ−25\lambda-25. According to the question, 75 \lambda-25=75 \Rightarrow \lambda=43\frac{4}{3}
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